NLM Quick Guide - In-Text References
eWithin the text of a publication, individual references are presented in an abbreviated format that refers back to the list. These abbreviated references within the text are called "in-text references."
In the citation-sequence system, numbers are used to refer to the reference list. References are numbered in the list in the order they first appear in the text. For example, if a reference by Zelinski is the first one referred to in the text, then the Zelinski reference is number one in the list.
Note: There are three ways in which in text citations can be formatted for this quick guide we have only included the above, for each of the other varieties there are implications in relations to creating a reference list. For a description of how to cite using either of the other formats Click Here