APA (7th ed.) Citation

Schumann, W., Bradshaw, R., & Mills, K. A. G. (1993). Handbook of rocks, minerals, and gemstones. Houghton Mifflin.

Chicago Style (17th ed.) Citation

Schumann, Walter, R. Bradshaw, and K. A. G. Mills. Handbook of Rocks, Minerals, and Gemstones. Boston, MA: Houghton Mifflin, 1993.

MLA (9th ed.) Citation

Schumann, Walter, et al. Handbook of Rocks, Minerals, and Gemstones. Houghton Mifflin, 1993.