1. Birch, R.R. (1984). J. Am. Oil Chem. Soc. 61, 340.
2. Birch, R.R. (1991). Riv. Ital. Sostanze Grasse, LXVIII, 433.
3. Bock, K.J., Huber, L. and Schöberl, P. (1988). Tenside 25, 86.
4. EEC Directive 73/404 with amendments 82/242 and 86/94.
5. EEC Directive 91/325 and 93/21.