"Diary microbiology." . . . . "Bulletin No. 642, Bureau of Animal Industry." . . . "The four essential Factors in the Production of Milk of low bacterial Content" . . . "The Four Essential Factors in the Production of Milk of Low Bacterial Content. By S. Henry Ayers, Lee B. Cook, and Paul W. Clemmer"@en . . . . . . . . . . . . . . . . . . . . . . . . "The four essential factors in the production of milk of low bacterial content"@en . . "Four essential factors in production of milk of low bacterial content"@en . . .