1. See short review A. DYER, Anal. Proc., 30 (1993) 190.
2. A convenient review is that by R. M. BARRER in Proc. 5th Int. Conf. on Zeolites, L. V. C. REES (Ed.), Heyden, London, 1980, p. 273.
3. H. MIMURA, T. KANNO, Tohoku Daigaku Senko Seiren Kenkyusho Iho, 34 (1978) 58.
4. H. MIMURA, I. ISEKI, K. KUDO, T. KANNO, Tohoku Daigaku Senko Seiren Kenkyusho Iho, 40 (1984) 27.
5. R. J. MANGABHAI, Univ. of Salford, personal communication.