AHFS Drug Information by Authoritative publication from American Hospital Formulary Service
Drug Facts and Comparisons by Frequently-updeated looseleaf publication. Comprehensive information on each drug, on warnings, side effects, and interactions
The Merck Index by Standard source of information on drugs, chemicals, and biologicals.
Dorland's Illustrated Medical Dictionary by 
Stedman's Medical Dictionary for the Health Professions and Nursing by 
