1. Little, C. The Colonisation of Land: Origins and Adaptations of Terrestrial Animals (Cambridge University Press, 1983).
2. Little, C. The Terrestrial Invasion: an Ecophysiological Approach to the Origins of Land Animals (Cambridge University Press, 1990).
3. Beerbower, R. in Geological Factors and the Evolution of Plants (ed. Tiffney, B. H.) 47–91 (Yale University Press. New Haven, 1985).
4. Kubiena, W. L. Micromorphological Features of Soil Geography (Rutgers Univesrity Press, New Brunswick, 1970).
5. Schumm, S. A. Geol. Soc. Am. Bull. 79, 1573–1588 (1968).