1. Hay, W. W. & Mohler, H. P. J. Paleont. 41, 1505–1541 (1967).
2. Pautard, F. G. E. Biological Calcification; Cellular and Molecular Aspects (ed. Schraer, H.) 140–141 (North-Holland, Amsterdam, 1970).
3. Klaveness, D. thesis, Oslo Univ. (1971).
4. de Jong, L. W., Dam, W., Westbroek, P. & Crenshaw, M. A. in The Mechanisms of Mineralisation in the Invertebrates and Plants (eds Watabe, N. & Wilbur, K. M.) 135–153 (University of South Carolina Press, 1976).
5. Hay, W. W. in Geology and Archaeology of Northern Cyrenaica, Libya (ed. Barr, F. T.) 149–157 (Petroleum Exploration Society of Libya, 1968).