APA (7th ed.) Citation

Boas, F., Hallowell, A. I., & Sapir, E. (1911). Linguistics materials, Frank G. Speck Papers.

Chicago Style (17th ed.) Citation

Boas, Franz, A. Irving Hallowell, and Edward Sapir. Linguistics Materials, Frank G. Speck Papers. 1911.

MLA (9th ed.) Citation

Boas, Franz, et al. Linguistics Materials, Frank G. Speck Papers. 1911.