Haggard, H. W., & Greenberg, L. A. (1935). Diet and physical efficiency: The influence of frequency of meals upon physical efficiency and industrial productivity. Yale university press; London, H. Milford, Oxford university press.

Haggard, Howard Wilcox, and Leon Arnold Greenberg. Diet and Physical Efficiency: The Influence of Frequency of Meals upon Physical Efficiency and Industrial Productivity. New Haven: Yale university press; London, H. Milford, Oxford university press, 1935.

Haggard, Howard Wilcox, and Leon Arnold Greenberg. Diet and Physical Efficiency: The Influence of Frequency of Meals upon Physical Efficiency and Industrial Productivity. Yale university press; London, H. Milford, Oxford university press, 1935.