1. Hilder, M.H., JAOCS 45:703–707 (1968).
2. Okkerse, C., “Submicroporous and Macroporous Silica,” Dissertation, University of Technology, Delft, The Netherlands, 1961, p. 42–46.
3. The Chemical Rubber Co., “Handbook of Chemistry and Physics,” 47th Edition, Cleveland, 1966, p. D106–107.
4. Van der Sluijs, W.L.N., “De Continue Hydrolyse van Vetten,” Dissertation, University of Technology, Eindhoven, The Netherlands, 1967, p. 65–66, 141.
5. Parsons, L.B., and C.O. Holmberg, Oil Soap 14:239–241 (1937).