The latest edition (10th ed., 2007) of the AMA Manual of Style is available online and in print, including on C Level in Science Reference.
The Council of Science Editors has its own writing and publication style.
The style known as "Vancouver" was created by the International Committee of Medical Journal Editors (ICMJE). It is used by many biomedical journals including Annals of Internal Medicine, British Medical Journal (BMJ), JAMA (Journal of the American Medical Association), and New England Journal of Medicine (NEJM).
Here are the organization's guidelines for preparing a manuscript for submission
In the References section of that page, there is a lot of guidance, including
Some journals use variations on Vancouver style. For style points that vary -- e.g., whether to cite electronic references within parentheses in the text or in numbered references following the text -- you should consult the specific journal to which you plan to submit your manuscript.