1. Baker, C.D. (1991) Recommended Methods of Analysis, Institute of Brewing, London.
2. BSI 3286: Assessment of quaternary ammonium compounds (1960). British Standards Institute, London.
3. Categorisation of pathogens according to hazard and categories of containment. (1984) Advisory Committee on Dangerous Pathogens, H.M.S.O., London.
4. Cook, A.H. (1963) Proceedings of the European Brewery Congress, Brussels, 477.
5. Flannigan, B. (1983) Journal of the Institute of Brewing, 89, 364.