APA (7th ed.) Citation

Symes, R. F., & Harding, R. R. (1991). Crystal & gem / written by R.F. Symes and R.R. Harding. Dorling Kindersley in association with the Natural History Museum.

Chicago Style (17th ed.) Citation

Symes, R. F., and R. R. Harding. Crystal & Gem / Written by R.F. Symes and R.R. Harding. London: Dorling Kindersley in association with the Natural History Museum, 1991.

MLA (9th ed.) Citation

Symes, R. F., and R. R. Harding. Crystal & Gem / Written by R.F. Symes and R.R. Harding. Dorling Kindersley in association with the Natural History Museum, 1991.

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