1. Estimating phytogenies at low taxonomic levels
2. and (1986) The nature, origin and fate of Homo erectus. In and (eds.): Major Topics in Primate and Human Evolution. Cambridge: Cambridge University Press, pp. 295–316.
3. (1977) Cladistic classification as applied to vertebrates. In , and (eds.): Major Patterns in Vertebrate Evolution. New York: Plenum Press, pp. 741–804.
4. (1981) Problems of Species Concepts in Palaeontology. Inter. Symp. Concept. Paleontol. Barcelona. pp. 19–34.