APA (7th ed.) Citation

Webster, R. (1983). Gems: Their sources, descriptions and identification (4. ed.). Butterworths.

Chicago Style (17th ed.) Citation

Webster, Robert. Gems: Their Sources, Descriptions and Identification. 4. ed. London u.a: Butterworths, 1983.

MLA (9th ed.) Citation

Webster, Robert. Gems: Their Sources, Descriptions and Identification. 4. ed. Butterworths, 1983.

Warning: These citations may not always be 100% accurate.