The American Medical Association (AMA) Manual of Style: A Guide for Authors and Editors is an online, searchable guide on creating a manuscript. Topics covered include: authorship, terminology, quantitation, and preferred usage.
This style guide provides rules and examples for creating references for a wide variety of sources. It does not discuss creating superscript citations or writing style. The National Library of Medicine (NLM) created and maintains this guide. It is available free and no log in is required.
The International Committee of Medical Journal Editors (ICMJE) developed these recommendations to review best practice and ethical standards in the conduct and reporting of research and other material published in medical journals, and to help authors, editors, and others involved in peer review and biomedical publishing create and distribute accurate, clear, reproducible, unbiased medical journal articles.