APA (7th ed.) Citation

Nugent, R. L., & Roberts, L. E. (1931). Determination of magnetite in copper slags. [publisher not identified].

Chicago Style (17th ed.) Citation

Nugent, R. L., and Lathrop E. Roberts. Determination of Magnetite in Copper Slags. Washington, D.C.: [publisher not identified], 1931.

MLA (9th ed.) Citation

Nugent, R. L., and Lathrop E. Roberts. Determination of Magnetite in Copper Slags. [publisher not identified], 1931.