1. K. K. Unger, “Porous Silica — Its Properties and Use as a Support in Column Liquid Chromatography”, Elsevier, Amsterdam, Oxford, New York, 1979, and references cited therein.
2. R. K. Iler, “The Chemistry of Silica — Solubility, Polymerization. Colloid and Surface Properties, and Biochemistry”, John Wiley & Sons, Inc., New York, 1979, and references cited therein.
3. B. W. Wright, M. L. Lee, S. W. Graham, L. V. Phillips, D. M. Hercules, J. Chromatogr.199, 355 (1980).
4. M. L. Hair, J. Non-Cryst. Solid19, 299 (1975).
5. B. W. Wright, M. L. Lee, unpublished results.