APA (7th ed.) Citation

Geological Survey (U.S.) & ProQuest (Firm). (1916). Bulletin 621. Contributions to economic geology (short papers and preliminary reports). 1915. [publisher not identified].

Chicago Style (17th ed.) Citation

Geological Survey (U.S.) and ProQuest (Firm). Bulletin 621. Contributions to Economic Geology (short Papers and Preliminary Reports). 1915. Washington: [publisher not identified], 1916.

MLA (9th ed.) Citation

Geological Survey (U.S.) and ProQuest (Firm). Bulletin 621. Contributions to Economic Geology (short Papers and Preliminary Reports). 1915. [publisher not identified], 1916.

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