1. Y. M. de Haan: `Kristalbouw en roosterenergie van laagstructuren van het type cadmiumhydroxyde’, PhD-thesis Technische Hogeschool Delft, Netherlands, 1965.
2. W. Feitknecht and H. R. Oswald: Helv. Chim. Acta 49 (1966), 344.
3. W. Feitknecht, P. Brunner, and H. R. Oswald: Z. Anorg. Allg. Chem. 316 (1962), 154.
4. H. R. Oswald, W. Feitknecht, and P. Brunner: in From Molecule to Cell: Symposium on Electron Microscopy, Modena, 1963, (ed. by P. Buffa ), CNR Roma, 1964, p. 141.
5. F. Freund: Fortschr. chem. Forsch. 10 (1968), 347.