Letter: Chemical versus chemotaxonomic or biotaxonomic classification.
D000970:Antineoplastic Agents / Q000145:classification; D055598:Chemical Phenomena; D002621:Chemistry; D002965:Classification; D004364:Pharmaceutical Preparations / Q000145:classification*; D010946:Plants, Medicinal
D000970:Antineoplastic Agents; D004364:Pharmaceutical Preparations