APA

Schaller W. T., . (1918). Gems and precious stones in 1916. Washington, D.C: Government Printing Office.

Chicago

Schaller Waldemar T, . 1918. Gems and precious stones in 1916. Washington, D.C: Government Printing Office.

Harvard

Schaller W. T., . (1918). Gems and precious stones in 1916. Washington, D.C: Government Printing Office.

MLA

Schaller Waldemar T, . Gems and precious stones in 1916. Washington, D.C: Government Printing Office. 1918.