AMA Style: How Do I Cite?

Anonymous works:

• If there is no named author, follow the citation style for the item, and omit the author name field. 
• If the item is really authored by a person going by the name Anonymous, use the word "Anonymous" as if it were a complete name of the author, and then use the appropriate style.

Author names in all references:

• Resources with 1-6 authors or editors, list all author or editor names.
• Resources with 7 or more authors or editors, list the first three, then abbreviate with et al. 

Capitalization of titles in reference list:

• For journal article titles and book chapters: capitalize the first letter of the first word, proper names, names of trials or study groups, and abbreviations.
• For titles of books and government documents, capitalize the first letter of each major word, but not articles, prepositions of less than 3 letters, conjunctions, or infinitives.

(note: No guidance is provided regarding capitalization for titles of conference materials, titles of journals, or other titles used in AMA citations.)

Journal Abbreviations can be found by looking at the Journal Record in the NLM catalogue (PubMed).  If your title is not in the PubMed catalog, the AMA Handbook offers advice for abbreviating journal titles in Chapter 13. For words that aren't in Chapter 13's list, you can look up the keywords from the title in the NMLA catalog or the CASSI search tool to see how other titles with the same word have been abbreviated.

One word titles are never abbreviated, and the complete title can always be used if an abbreviation cannot be found.