Author variations apply to all reference types (books, journal articles, reports etc.). Author surnames (family names) are followed by their two-letter initials with no space or full stop between the initials, e.g. Smith JA. Commas are used to separate each author's name, e.g. Khan FM, Gibbons JP.
Titles should appear in lower case except for the first letter of the first word, abbreviations, proper names, and names of clinical trials or study groups, e.g.
Krieger J, Song L, Philby M. Community health worker home visits for adults with uncontrolled asthma: the HomeBASE Trial randomized clinical trial. JAMA Intern Med. 2015;175(1):109-117. doi:10.1001/jamainternmed.2014.6353
Titles of whole works such as journals and books, should appear in headline style capitalisation, where all significant words start with a capital letter.
A Digital Object Identifier (DOI), is a string of numbers, letters and symbols that creates a permanent link to a journal article, book or other online document, e.g. 10.1108/HER-10-2015-0023. In the Vancouver style, DOIs are presented as metadata, not as hyperlinks, e.g. doi:10.1001/jamainternmed.2014.6353
Journal titles are abbreviated in the Vancouver style, e.g. New England Journal of Medicine appears as N Engl J Med in the reference list entry. A list of abbreviations is available through PubMed at: https://pubmed.ncbi.nlm.nih.gov/. Click on Journals (under Explore) and enter the full journal title to view its abbreviation. Alternative sources of journal title abbreviations are listed in appendix B of Citing Medicine.