APA (7th ed.) Citation

Annell, C. S., & Helz, A. W. (1961). A constant-feed direct-current arc. United States Department of the Interior, Geological Survey.

Chicago Style (17th ed.) Citation

Annell, C. S., and A. W. Helz. A Constant-feed Direct-current Arc. Washington, D.C.: United States Department of the Interior, Geological Survey, 1961.

MLA (9th ed.) Citation

Annell, C. S., and A. W. Helz. A Constant-feed Direct-current Arc. United States Department of the Interior, Geological Survey, 1961.