1. G.D. Stuky, S.R. Marder, J.E. Sohn, Materials for Nonlinear Optics (Am. Chem. Soc., Washington D.C., 1991).
2. J. Fricke, R. Caps in Ultrastructure Processing of Advanced Ceramics, edited by J.D. Mackenzie and D.R. Ulrich (John Wiley & Sons, New York, 1990), p. 613.
3. L.L. Hench, M.J.R. Wilson, J. Non-Cryst. Solids 121, 234 (1990).
4. S.H. Wang, C. Campbell, L.L. Hench in Ultrastructure Processing of Advanced Ceramics, edited by J.D. Mackenzie and D.R. Ulrich (John Wiley & Sons, New York, 1990), p. 145.
5. T. Takada, T. Yano, A. Yasumori, M. Yamane, J.D. Mackenzie, J. Non-Cryst, Solids 147, 631 (1992).