1. (1) H. Mills : J. Oil & Colour Chemists' assoc., 34,497 (1951)
2. (2) A. Goeb : Farb u. Lack, 57 (1951)
3. (3) H. Rabalé : ibid, 16, 51, 68, 90,115,137 (1939)
4. (4) R. Nitschké : Farben Ztg., 45,688,708 (1940)
5. (5) P. C. Williams : Disc. Faraday Soc., 11, 47 (1951)