1. Anon. (1971). The Ad Hoc Committee on Enzyme Detergents: Report PB 204 118, Division of Medical Sciences, National Academy of Sciences — National Research Council, Enzyme-containing laundering compounds and consumer health
2. Aunstrup, K. (1980). Proc. Microbial Ind. Alim. Conf. Int. (1979) 77–96, Micro-organisms as producers of enzymes
3. Balls, A. K. (1941). U.S. Dept. Agriculture, Circular No. 631, Protein-digesting enzymes of papaya and pineapple, Washington DC
4. Barretts De Menezes, T. J. (1982). Process Biochem., 17(3), 32–35, Starchy materials for alcohol fuel production
5. Bender, H. and Wallenfels, K. (1961). Biochem. Z., 334, 79–95, Pullulan II specific decomposition by a bacterial enzyme