Macy, L. K., Arnold, L. E., McKibben, E. G., & Stone, E. J. (1937). Changes in technology and labor requirements in crop production: Sugar beets. s.n.
Cita Chicago (17th ed.)Macy, Loring K., Lloyd E. Arnold, Eugene George McKibben, i Edmund Jefferson Stone. Changes in Technology and Labor Requirements in Crop Production: Sugar Beets. Philadelphia, Pa: s.n, 1937.
Cita MLA (9th ed.)Macy, Loring K., et al. Changes in Technology and Labor Requirements in Crop Production: Sugar Beets. s.n, 1937.
Atenció: Aquestes cites poden no estar 100% correctes.