Cita APA (7a ed.)

Elwood, R. B., Arnold, L. E., D Clarence Schumutz, & Mc Kibben, E. G. (1939). Changes in technology and labor requirements in crop production; wheat and oats. National Research Proyect.

Cita Chicago Style (17a ed.)

Elwood, Robert B., Lloyd E. Arnold, D Clarence Schumutz, y Eugene G. Mc Kibben. Changes in Technology and Labor Requirements in Crop Production; Wheat and Oats. Philadelphia: National Research Proyect, 1939.

Cita MLA (8a ed.)

Elwood, Robert B., et al. Changes in Technology and Labor Requirements in Crop Production; Wheat and Oats. National Research Proyect, 1939.