• Use secondary sources sparingly; you should always try to locate the original source of information which is cited in a work that you have read. This is, however, not always possible: sometimes the original work is out of print, unavailable through your usual sources or not available in English.
• Reference may be made to an author's citation of, or quotation from, another's work.
• Distinguish between works cited and quoted.
• In the text, the name of the original author, rather than the secondary source, should be mentioned.
Citing
1. Gordis E. Relapse and craving: a commentary. Alcohol Alert. 1989;6:3. Cited by Mason BJ, Kocsis JH, Ritvo EC, Cutler RB. A double-blind, placebo controlled trial of desipramine for primary alcohol dependence stratified on the presence or absence of major depression, JAMA. 1996;275:761-7.
Quoting
2. Charrow RP. PHS' Office of Scientific Integrity Review: housekeeping is in order. J NIH Res. 1991;3:103-6. Quoted by Rennie D, Gunsalus CK. Scientific misconduct: new definition, procedures, and office - perhaps a new leaf. JAMA. 1993;269:915-7.