1. Some observations on the determination of the activity of rennet;Berridge;Analyst,1952
2. BMD—Biomedical Computer Programs. 1971. University of California Press, Berkeley.
3. Ernstrom, C. A. Page 687 in Fundamentals of dairy chemistry. 1974. B. H. Webb, A. H. Johnson, and J. A. Alford, ed. 2nd ed. Avi Publ. Co., Westport, CT.
4. Ibid., p. 690.