References
- Method I: Gray, P. P., and Stone, I. M. Wallerstein Labs. Communs. 5: 5 (1939).
- Method II: DeClerck, J., and Van Cauwenberge, E. H. Wallerstein Labs. Communs. 20: 255 (1957).
- Method III: Owades, J. L., and Zientara, F. Am. Soc. Brewing Chemists, Proc. 1960, p. 68.
- Method IV: Roberts, M., Laufer, S., and Stewart, E. D. Am. Brewer 82 (1): 34 (1948).