1. Gordon, M., Cowie, I.M.G., Goldsbrough, J., Ready, B.W., British Pat. 1,377,478 (1971);
2. US Patent 3,807, 865 (1974)
3. Galina, H., Gordon, M., Irvine, P., Kleintjens, L.A., Pure Appl. Chem., 54 (1982) 365
4. Koningsveld, R., Kleintjens, L.A., this Volume
5. Derham, K.W., Goldsbrough, J., Gordon, M., Pure Appl.Chem., 38 (1974) 97