A field study on Sumatran orang-utans (Pongo pygmaeus abelii): ecology, behaviour and conservation.
1978. Octavo, photographs, softcover. More
1978. Octavo, photographs, softcover. More
Princeton: Princeton University Press, 1992. Octavo, text illustrations, very good copy in dustwrapper. More
Chicago: University of Chicago Press, 1975. Octavo, photographs, dustwrapper. More