1. (1977) Ecology and Behavior of Noctrunal Primates. New York: Columbia.
2. (1936) The problem of the cla. In primates. Proc. Zool. Soc. Part I: 1–24.
3. (1959) The Antecedents of Man. Edinburgh: Edinburgh Univ. Press.
4. (1984) Foraging, habitat structure, and locomotio. In two species of Galago. In and (eds): Adaptations for Foraging in Nonhuman Primates. New York: Columbia, pp. 73–111.