1. T.E. Lefort (to Societe Francaise de Catalyse Generalisee), Fr. Patent No. 729,952 (March 27, 1931) and subsequent additions.
2. R.P. Nielsen and J.H. LaRochelle, US Patent No. 3 962 136 (1976) and US Patent No. 4 012 425 (1977).
3. The Mechanism of Ethylene Epoxidation