Numeric citation system
Also called: numbered citations, citation-sequence
A citation system where sources are numbered in order of first appearance and the in-text marker is that number.
Vancouver, IEEE, AMA, Nature, and most physical-science journal styles are numeric. The first source cited is 1, the second 2, and the reference list is ordered by number rather than alphabetically. IEEE brackets the number, Vancouver parenthesises or superscripts it, Nature superscripts it.
The appeal is density: a sentence can carry six citations as “[1]–[6]” without becoming unreadable, which suits fields where a claim rests on many prior results. The cost is that the reader learns nothing about a source without turning to the list, and that inserting a citation renumbers everything after it — which is why numeric styles and manual numbering are a bad combination.
A variant, citation-name, numbers an alphabetised list instead, so the numbers do not follow the text order.