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How to Cite Two Works by the Same Author in the Same Year

When one author or one identical author list publishes twice in a year, an author–date citation stops pointing at a single reference-list line. APA 7 §§8.19 and 9.47 and Chicago 18 author-date solve that with a lowercase letter after the year. MLA 9 never used the year as the key, so it adds a shortened title and, in the ninth edition, may replace a repeated identical author line with three hyphens. This is the disambiguation workflow, not the author-count page or the cite-the-same-source-again page. List-wide order lives in how to write a bibliography.

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How to Cite the Same Author in the Same Year: Quick Answer

Build the finished list first, then letter or shorten from that order. In APA 7, compare dates before titles: a year-only date precedes a more specific date in the same year, then identical dates sort by title, ignoring an initial A, An, or The. The first of those lines becomes 2012a or 2020a in the reference and in every in-text citation. Chicago author-date uses the same letters, with no comma between name and year. MLA 9 and Chicago notes-bibliography keep titles in the citation, so they do not add year letters.

Templates (swap in your author, year, and title)

APA 7 references:

Author, A. A. (Yeara). First title … / Author, A. A. (Yearb). Second title …

APA 7 in-text:

(Author, Yeara); (Author, Yearb); both at once (Author, Yeara, Yearb)

MLA 9 works cited:

Author, First. First Title. … / ---. Second Title. …

MLA 9 in-text:

(Author, Short Title Page); (Author, "Short Article" Page)

Chicago 18 shortened notes:

2. Author, "Short Title," Page. / 3. Author, "Other Short Title," Page.

Chicago 18 bibliography:

Author, First. "First Title." … / Author, First. "Second Title." … (name repeated; no 3-em dash)

Chicago 18 author-date:

Author, First. Yeara. … / Author, First. Yearb. … and (Author Yeara, Page)

Official APA 7 letter-assignment wording (UAB reprint of §§8.19 and 9.47)

To distinguish between these works, put a lowercase letter after the year in both the in-text citation and the reference list.
Letter format for references with years is "2020a," "2020b."
Letter format for references with no date is "n.d.-a," "n.d.-b."
Letter format for references in-press is "in press-a," "in press-b."
Assigning letters is a two-step process. First, compare dates. References with only a year precede those with more specific dates, and specific dates are placed in chronological order.
Arrange works with the same author(s) and same year alphabetically by title in the reference list. This then determines which references uses a, b, c etc.
However, if references with the same author and date are identified as articles in a series (e.g., Part 1 and Part 2), order the references in the series order, regardless of the titles' alphabetical order.

The first five sentences are the University of Alabama at Birmingham APA 7 citing page reprint of the Publication Manual, opened 19 September 2026. The title-order sentence is the University of Queensland APA 7 reference-list page restatement of the same rule, including the year-only-before-month pattern on that page. The series exception is the Publication Manual wording reprinted in the MDPI APA 7 reference-list guide. Ignore an initial A, An, or The when you alphabetize those titles. The APA Style citations hub and references hub are the official homes for §§8.19 and 9.47.

Why the year alone stops working

An author–date citation is a lookup key. (Judge & Kammeyer-Mueller, 2012) promises that exactly one reference-list line starts with those names and that year. The moment a second 2012 line by the same authors appears, every citation to either paper is ambiguous unless the year carries a letter. Author–page systems such as MLA never used the year as that key, so they reach for a shortened title instead. The letters APA requires are therefore a mistake in MLA.

The letters follow the finished list, not the order you first cited the works and not, when the dates are identical, the month on the title page. A late addition whose title sorts between two already-lettered works can change a and b. Numbered parts of a series (Part 1, Part 2) are the one APA exception: they keep series order even when the titles would sort the other way.

APA 7: 2012a and 2012b from the Publication Manual

The worked pair in APA 7 §§8.19 and 9.47 is Timothy A. Judge and John D. Kammeyer-Mueller's two 2012 articles. General and specific measures sorts before On the value of aiming high, so the Journal of Organizational Behavior paper is 2012a and the Journal of Applied Psychology paper is 2012b. Both DOIs resolve. Use those letters in the reference list and in every in-text citation, including the first.

Official APA 7 same-author, same-year pair

References (title order):

Judge, T. A., & Kammeyer-Mueller, J. D. (2012a). General and specific measures in organizational behavior research: Considerations, examples, and recommendations for researchers. Journal of Organizational Behavior, 33(2), 161–174. https://doi.org/10.1002/job.764

Judge, T. A., & Kammeyer-Mueller, J. D. (2012b). On the value of aiming high: The causes and consequences of ambition. Journal of Applied Psychology, 97(4), 758–775. https://doi.org/10.1037/a0028084

Parenthetical, one work:

(Judge & Kammeyer-Mueller, 2012a)

Narrative:

Judge and Kammeyer-Mueller (2012b) found that …

Both works together:

(Judge & Kammeyer-Mueller, 2012a, 2012b)

Quotation with a page from the 2012a range:

(Judge & Kammeyer-Mueller, 2012a, p. 169)

When both works sit in one parenthetical, APA §8.12 gives the author names once and the lettered years in order, separated by commas. Do not write (Judge & Kammeyer-Mueller, 2012a; Judge & Kammeyer-Mueller, 2012b). The semicolon form is for different author lists. Some university handouts repeat the names with a semicolon anyway; that is the multiple-works layout from Table 8.1, not the same-author layout. The in-text citation generator will accept 2012a in the year field. Journal formatting itself is on how to cite a journal article in APA.

Step one is the date, not the title

The old shortcut "always letter by title" is incomplete. APA first compares the date element. A reference that is only (2020) precedes (2020, March 26), which precedes (2020, April 2). Title order is the tie-breaker for identical dates. The Publication Manual's teaching names for that two-step sequence are Azikiwe and Bello (same year, different specificity) and Patel (n.d. before dated years, in press last).

Official APA 7 date-order templates (Publication Manual teaching names)

Year-only before a more specific date:

Azikiwe, H., & Bello, A. (2020a).

Azikiwe, H., & Bello, A. (2020b, March 26).

Azikiwe, H., & Bello, A. (2020c, April 2).

One author across date types:

Patel, S. N. (n.d.).

Patel, S. N. (2016).

Patel, S. N. (2020a).

Patel, S. N. (2020b, April).

Patel, S. N. (in press).

Those lines are official APA teaching templates, not articles to retrieve. If your two posts are (2020, March 2) and (2020, September 14), March is 2020a even if the September title would sort first. If both posts are dated only 2020, then title order decides the letters.

No date and in press: n.d.-a, in press-a

APA treats n.d. and in press as dates, so they can collide too. Add the letter after a hyphen: n.d.-a, n.d.-b, in press-a, in press-b. The hyphen exists because n.d.a would be unreadable; a numeric year does not take that hyphen. The no-date guide is the recovery workflow; the official colliding pair there is two Merriam-Webster entries.

Official APA 7 undated pair (Common Reference Examples / no-date guide)

References, title order:

Merriam-Webster. (n.d.-a). Reflective. In Merriam-Webster.com dictionary. Retrieved September 6, 2021, from https://www.merriam-webster.com/dictionary/reflective

Merriam-Webster. (n.d.-b). Semantics. In Merriam-Webster.com dictionary. Retrieved September 6, 2021, from https://www.merriam-webster.com/dictionary/semantics

In-text:

(Merriam-Webster, n.d.-a); (Merriam-Webster, n.d.-b)

In-press template (not a real article):

Author, A. A. (in press-a). First forthcoming title. Journal Name.

Author, A. A. (in press-b). Second forthcoming title. Other Journal.

In-text, in press:

(Author, in press-a, in press-b)

Where the pair sits in the full reference list

APA orders one author's solo works by year, earliest first. Letters only distinguish works inside one year. A solo entry always precedes a co-authored entry that starts with the same surname, regardless of year, so a 2019 solo paper still sits above a 2012 co-authored paper. Co-authored entries then sort by the second author's surname. The bibliography alphabetizer applies that order; how to cite multiple authors covers the et al. collision that is not solved with letters.

Not this problem: same surname, different people

Letters are for one author list with two works. If two different people share a surname, APA distinguishes them with initials in the text — (J. M. Taylor, 2015) and (T. Taylor, 2014) in the Publication Manual's pairing — and gives no letters. If two multi-author works from the same year shorten to the same et al. form, APA adds names until the citations differ, again with no letters. Check which situation you have before you reach for a and b.

MLA 9: shortened titles, and a 2026 change coming for the dash

MLA 9 does not use year letters. Its parenthetical is author–page, so when the list holds two works by one author the citation adds a shortened title after the name, with a comma between name and title and no comma before the page. MLA Handbook §6.8 is the same-author rule; §6.10 is how far to shorten. The MLA Style Center still shows three hyphens for an identical author line in the ninth edition, but a 10 June 2026 note already lets you repeat the name.

Official MLA Style Center wording, 10 June 2026

According to the ninth edition of the MLA Handbook, three em dashes or three hyphens can take the place of identical names in consecutive works-cited-list entries (sec. 5.126), but using dashes and hyphens in that way can cause accessibility issues for users of screen readers and other assistive technologies.
With that in mind, future editions of the handbook will no longer recommend using dashes or hyphens. Instead, MLA style will advise repeating names in full in the Author element of consecutive works-cited-list entries, so the information is clear to everyone.
You are welcome to use either style—using dashes or hyphens, or writing out all names in full—in advance of the next handbook edition, as long as your instructor doesn’t object to your deviating from the guidance published in the ninth edition.

That note is the live MLA Style Center accessibility post of 10 June 2026. For a student paper following the printed ninth edition, three hyphens plus a period (---.) are still correct. Repeating the name is already acceptable if your instructor agrees, and it matches where Chicago already moved.

The two 1992 books below are a real same-author, same-year pair. Jazz sorts before Playing in the Dark. MLA would use the same short-title rule if the years differed; the year is not the key.

MLA 9, two 1992 books by Toni Morrison

Works cited (title order, ninth-edition hyphens):

Morrison, Toni. Jazz. Knopf, 1992.

---. Playing in the Dark: Whiteness and the Literary Imagination. Harvard UP, 1992.

Same list with the name repeated (already allowed):

Morrison, Toni. Jazz. Knopf, 1992.

Morrison, Toni. Playing in the Dark: Whiteness and the Literary Imagination. Harvard UP, 1992.

Parenthetical:

(Morrison, Jazz 45)

(Morrison, Playing 17)

Author named in the sentence:

Morrison describes that opening (Jazz 45).

Author and title in the sentence:

In Jazz, Morrison describes that opening (45).

Shorten to the first noun and any adjectives in front of it, and drop an initial A, An, or The. Keep the full title's formatting: italics for a book, quotation marks for an article. Playing in the Dark: Whiteness and the Literary Imagination therefore shortens to Playing, not to the subtitle. If two titles share a first noun, keep enough words to tell them apart. Book-entry punctuation is on how to cite a book in MLA; the general parenthetical is on the MLA in-text guide.

When the three hyphens may not be used

  • The name line must be identical. The hyphens stand for exactly the Author element above them. A work by Morrison and another writer gets both names written out.
  • A different role needs the role after the hyphens. If the second work is an edited collection, write ---, editor. rather than ---.
  • Solo before co-authored. All of one author's solo works come first, alphabetised by title; works with co-authors follow, alphabetised by the co-author's surname.
  • *Ignore A, An, and The*** when alphabetising titles, but keep them in the entry.
  • No year letters anywhere. (Morrison 1992a) is an APA habit that does not map onto an MLA list.

Chicago 18: repeat the name in bibliographies, letters in author-date

Chicago splits along its two systems. In notes-bibliography the note already carries the title, so nothing extra is needed to tell two works apart; the only decision is how to list them. In author-date the year is the key, so Chicago letters the year the way APA does. Both systems are in the live Notes and Bibliography and Author-Date Quick Guides. What's New in the 18th edition points at §§13.72 and 13.113 for the repeated name, and §13.114 for title order among one author's works.

Notes-Bibliography

CMOS 16 replaced a repeated author's name with a 3-em dash. CMOS 17 retired that recommendation. CMOS 18 keeps the change and states it as a preference, not a house-style leftover.

Official CMOS 18 What's New wording for §§13.72 and 13.113

Chicago now prefers repeating the name of the author(s) rather than using a 3-em dash to stand in for repeated names in bibliographies or reference lists.

Some publishers still insert the dash at typesetting. If yours does, that is a production choice, not a student-paper rule. An author's works in a bibliography sort by title, ignoring an initial A, An, or The (§13.100), whatever their years.

The two 2006 Latin American Antiquity articles below are the pair the CMOS Q&A uses for author-date letters. They work as notes too: thirteen authors shorten to Neff et al. in the note (CMOS 18: more than two authors), and the bibliography lists the first three plus et al. (more than six authors).

Chicago 18 notes-bibliography, Neff et al. 2006 pair

First note, work 1:

1. Hector Neff et al., "Methodological Issues in the Provenance Investigation of Early Formative Mesoamerican Ceramics," Latin American Antiquity 17, no. 1 (2006): 60, https://doi.org/10.2307/25063036.

First note, work 2:

2. Hector Neff et al., "Smokescreens in the Provenance Investigation of Early Formative Mesoamerican Ceramics," Latin American Antiquity 17, no. 1 (2006): 110, https://doi.org/10.2307/25063039.

Shortened notes:

3. Neff et al., "Methodological Issues," 62.

4. Neff et al., "Smokescreens," 112.

Bibliography (name repeated, title order):

Neff, Hector, Jeffrey Blomster, Michael D. Glascock, et al. "Methodological Issues in the Provenance Investigation of Early Formative Mesoamerican Ceramics." Latin American Antiquity 17, no. 1 (2006): 54–76. https://doi.org/10.2307/25063036.

Neff, Hector, Jeffrey Blomster, Michael D. Glascock, et al. "Smokescreens in the Provenance Investigation of Early Formative Mesoamerican Ceramics." Latin American Antiquity 17, no. 1 (2006): 104–18. https://doi.org/10.2307/25063039.

Shortened notes are what make the notes system work: after the first full note, every later reference is author plus shortened title plus page, so two works by one author list are never confused. The same-source guide covers shortened notes and ibid., the Chicago footnote generator produces both forms, and how to cite a journal article in Chicago is the article pattern.

Author-Date

Chicago author-date lists one author's works chronologically. Works from the same year are alphabetised by title (§13.114) and given a, b, c after the year in both the reference list and the text. There is no comma between author and year: (Neff et al. 2006a). The live CMOS Q&A on this exact pair, relying on the 18th edition, also allows a short-title alternative if you would rather not letter the year.

Official CMOS 18 Q&A wording and Neff samples

If the works are by the same author, assign letters to the dates in your reference list and refer to them (Jones 2000a, 2000b).
Yes, you can use letters to differentiate the two articles in your text.
Because the first three authors are identical for those two articles (each of which lists thirteen authors), adding a and b after the year of publication would distinguish them in the text.
Alternatively, you could cite by title in the text (and omit the letters in the reference list entries and text citations):

Reference list (CMOS Q&A, title order):

Neff, Hector, Jeffrey Blomster, Michael D. Glascock, et al. 2006a. "Methodological Issues in the Provenance Investigation of Early Formative Mesoamerican Ceramics." Latin American Antiquity 17 (1): 54–76. https://doi.org/10.2307/25063036.

Neff, Hector, Jeffrey Blomster, Michael D. Glascock, et al. 2006b. "Smokescreens in the Provenance Investigation of Early Formative Mesoamerican Ceramics." Latin American Antiquity 17 (1): 104–18. https://doi.org/10.2307/25063039.

Text citations (letters):

(Neff et al. 2006a)

(Neff et al. 2006b)

Text citations (title alternative from the same Q&A):

(Neff et al., "Methodological Issues," 2006)

(Neff et al., "Smokescreens," 2006)

The Jones sentence is the CMOS Q&A on shared surnames (17th-edition answer; the letter form did not change). The Neff sentences and samples are the live CMOS 18 Documentation Q&A on two 2006 Latin American Antiquity articles, opened 19 September 2026. Citing both lettered years together gives the author once: (Neff et al. 2006a, 2006b). A later Q&A allows an en dash for a consecutive run — (Author 2021a–2021d) — unless each year must remain a separate link.

The name is repeated in author-date reference lists for the same reason it is repeated in bibliographies. Solo works precede co-authored works that begin with the same name. Undated works take n.d. in the year slot; if two collide, letter them after the abbreviation, following title order. Different coauthor lists that would otherwise collapse to the same et al. year are an author-count problem: see multiple authors and CMOS 13.123.

Three styles side by side

APA 7

Key:

Year plus letter: 2012a, 2012b

Order:

Date first (year-only, then more specific); identical dates by title

List entry:

Name repeated; letter inside the date parentheses

In-text:

(Judge & Kammeyer-Mueller, 2012a, 2012b)

MLA 9

Key:

Shortened title

Order:

By title, ignoring A, An, The

List entry:

Name once, then ---. — or repeat the name (10 June 2026)

In-text:

(Morrison, Jazz 45)

Chicago 18

Key:

Notes: shortened title. Author-date: 2006a, 2006b

Order:

Bibliography: by title. Author-date: by year, then title

List entry:

Name repeated in full; no 3-em dash (What's New 13.72, 13.113)

In-text:

Neff et al., "Smokescreens," 112. or (Neff et al. 2006a)

Same author, same year: what changes in each style.
QuestionAPA 7MLA 9Chicago 18 notesChicago 18 author-date
Year letters?Yes, requiredNoNoYes, preferred; short title is an allowed alternative
What decides a versus bDate specificity, then title orderNot applicableNot applicableTitle order among the same year
Repeated name in the listRepeated--- from the second entry, or the name repeatedRepeated (preferred since CMOS 17)Repeated
Two works in one citation(Judge & Kammeyer-Mueller, 2012a, 2012b)(Morrison, Jazz 45; Playing 17)Two shortened notes, or one note with both(Neff et al. 2006a, 2006b)
No daten.d.-a, n.d.-bOmit the date; titles distinguishTitles distinguishn.d., with letters if two collide
Forthcomingin press-a, in press-bforthcoming in the date slot; titles distinguishforthcoming; titles distinguishforthcoming; add letters only if two collide
Comma between author and yearYesNo year in the citationNo year in the citationNo

A short checklist

Before you submit a list with two works by one author

  • I confirmed the works are by the same author list, not by two people who share a surname.
  • APA: I compared dates first (year-only before March-and-day), then sorted identical dates by title, ignoring A, An, and The.
  • APA and Chicago author-date: I put a, b, c after the year in the list and in every citation, including the first.
  • APA: I used n.d.-a and in press-a with a hyphen, and 2012a without one.
  • MLA: I added a shortened title in each parenthetical, with a comma after the name and none before the page, and I used ---. only for an identical author line — or I repeated the name.
  • Chicago: I repeated the name in each bibliography or reference-list entry instead of a 3-em dash.
  • I re-checked the letters after any late addition to the list, because a new title or a more specific date can change the order.

Common mistakes

  • Assigning a and b by the order you cited the works, or by month when APA still has a year-only date to place first.
  • Using letters in the reference list but not in the text, or in the text but not in the list. Both places, every time.
  • Writing (Judge & Kammeyer-Mueller, 2012a; Judge & Kammeyer-Mueller, 2012b) in APA for two works by the same authors. Give the names once: (Judge & Kammeyer-Mueller, 2012a, 2012b).
  • Writing 2012-a or n.d.a. Numeric years take no hyphen; n.d. and in press do.
  • Adding year letters in MLA, or a comma before the page number in an MLA parenthetical with a title.
  • Using ---. in MLA for a co-authored work that follows a solo work. The author line differs, so the names are written out.
  • Using a 3-em dash in a Chicago bibliography because an older template did. CMOS 17 and 18 repeat the name.
  • Writing (Neff et al., 2006a) in Chicago author-date. Chicago has no comma between author and year.
  • Forgetting to re-letter after adding a third same-year work whose title or date sorts between the first two.
  • Using letters to separate two different people who share a surname. That is initials (APA, Chicago) or a first name (MLA), not a and b.

Sort the list, then letter it

Generate each entry as normal, then alphabetise so same-author, same-year works fall into the order your style requires. Add the a and b letters in the year field for APA or Chicago author-date and let the in-text tool carry them into the citations. In MLA, the alphabetizer puts the works into the order the three hyphens — or the repeated name — depend on.

Bibliography alphabetizer →In-text citation generator →Journal article citation generator →

Frequently asked questions

How do I cite two works by the same author from the same year in APA?
Finish the reference list first. Compare dates, then sort identical dates by title, ignoring A, An, and The. Add lowercase letters after the year in both the list and the text: Judge and Kammeyer-Mueller's 2012 pair is (2012a) and (2012b). To cite both at once, write (Judge & Kammeyer-Mueller, 2012a, 2012b) with the names given once.
How are the a and b letters assigned in APA 7?
In two steps. First compare the date element: a year-only 2020 precedes 2020, March 26, which precedes 2020, April 2 — the official Azikiwe and Bello template. If the dates are identical, alphabetize by title. Do not assign letters by the order you cite the works. Numbered series (Part 1, Part 2) keep series order. A late addition can change the letters, so assign them from the finished list.
Does MLA use 2012a and 2012b?
No. MLA in-text citations are author–page, so two works by one author take a shortened title after the name: (Morrison, Jazz 45) and (Morrison, Playing 17). The same rule applies when the years differ. In the works-cited list, alphabetize by title and either replace the second identical author line with ---. or, after the 10 June 2026 Style Center note, repeat the name.
What do the three hyphens mean in an MLA works-cited list?
They stand for exactly the same Author element as the entry above. MLA 9 §5.126 still allows three hyphens or a 3-em dash. They may be used only when that name line is identical; a co-authored work following a solo work is written out, and a different role is added after the hyphens, as in ---, editor. The 10 June 2026 Style Center note already permits repeating the name for accessibility, and future editions will recommend that.
Does Chicago still use the 3-em dash for a repeated author?
Not as its preference. CMOS 17 replaced the dash with the repeated name, and the CMOS 18 What's New page for §§13.72 and 13.113 keeps that rule for bibliographies and author-date reference lists: "Chicago now prefers repeating the name of the author(s) rather than using a 3-em dash." Some publishers still insert the dash at typesetting.
How does Chicago author-date handle two works from one year?
Letter the year in title order and use those letters in the list and the text. The live CMOS 18 Q&A pair is Neff et al. 2006a (Methodological Issues) and 2006b (Smokescreens), cited as (Neff et al. 2006a) with no comma after the name. The same Q&A also allows (Neff et al., "Methodological Issues," 2006) if you would rather cite the short title and skip the letters.
What if the two works have no date, or are in press?
APA adds the letter after a hyphen: n.d.-a and n.d.-b, or in press-a and in press-b, after the usual date-then-title sort. The official undated pair is Merriam-Webster's Reflective (n.d.-a) and Semantics (n.d.-b) entries. MLA omits the date and relies on titles. Chicago author-date writes n.d. in the year slot and adds letters only if two undated works by the same author collide.
Two different authors share a surname and both published in 2020. Do I use letters?
No. Letters are for one author list with two works. For different people with the same surname, APA adds initials in the text; MLA adds a first name or initial the same way; Chicago uses a first initial, as in the CMOS Q&A's (R. Jones 2000; B. Jones 2000), and adds a short title only if the initials also match.
Can I cite both lettered years in one parenthetical?
Yes. APA and Chicago author-date give the author once and the years in order: (Judge & Kammeyer-Mueller, 2012a, 2012b) or (Neff et al. 2006a, 2006b). MLA puts both short titles in one parenthetical, separated by a semicolon: (Morrison, Jazz 45; Playing 17). Chicago notes usually become two shortened notes rather than one crowded note.