APA (7th ed.) Citation

Webster, R. (1994). Gems: Their sources, descriptions and identification (5. ed.). Butterworth-Heinemann.

Chicago Style (17th ed.) Citation

Webster, Robert. Gems: Their Sources, Descriptions and Identification. 5. ed. Oxford [u.a.]: Butterworth-Heinemann, 1994.

MLA (9th ed.) Citation

Webster, Robert. Gems: Their Sources, Descriptions and Identification. 5. ed. Butterworth-Heinemann, 1994.