"Instructions to authors" vary by journal, each having its own preference for how the article is submitted and formatted.  You can check in the journal itself or the journal's website, or one of the best listings is from the Mulford Health Science Library of the Medical College of Ohio.  They provides extensive links in their Instructions to Authors in the Health Sciences.

Rowan University Libraries also licenses the citation management tool, EndNote.  Endnote can organize your citations and format and cite references in the correct publication style used by many scholarly publications.