APA

Kraus E. H., Slawson C. B., . (1941). Gems and gem materials. New York: McGraw-Hill.

Chicago

Kraus Edward Henry, Slawson Chester Baker, . 1941. Gems and gem materials. New York: McGraw-Hill.

Harvard

Kraus E. H., Slawson C. B., . (1941). Gems and gem materials. New York: McGraw-Hill.

MLA

Kraus Edward Henry, Slawson Chester Baker, . Gems and gem materials. New York: McGraw-Hill. 1941.