APA (7th ed.) Citation

Fieldner, A. C., Frevert, H. W., & Katz, S. H. (1926). Gas mask for protection against ammonia gas. [publisher not identified].

Chicago Style (17th ed.) Citation

Fieldner, Arno Carl, H. W. Frevert, and S. H. Katz. Gas Mask for Protection Against Ammonia Gas. Washington, D.C.: [publisher not identified], 1926.

MLA (9th ed.) Citation

Fieldner, Arno Carl, et al. Gas Mask for Protection Against Ammonia Gas. [publisher not identified], 1926.