1. C.J. Brinker and G.W. Scherer, Sol-Gel Science: the Physics and Chemistry of Sol-Gel Processing (Academic Press, San Diego, 1990).
2. M.A. Aegerter, M. Jafelicci Jr., D.F. Souza and E.D. Zanotto, ed., Sol-Gel Science and Technology (World Scientific, Singapore, 1991).
3. H. Dislich, in Sol-Gel Technology for Thin Films, Preforms, Electronics, and Specialty Shapes, edited by L.C. Klein (Noyes Publications, Park Ridge, 1988), p. 50.
4. R.B. Pettit, C.S. Ashley, S.T. Reed, and C.J. Brinker, in Sol-Gel Technology for Thin Films, Preforms, Electronics, and Specialty, edited by L.C. Klein (Noyes Publications, Park Ridge, 1988), p. 80.
5. S. Sakka, Reference 2, p. 346.