Author: RIJKSEN, H.D.,
Title: A Fieldstudy on Sumatran Orang Utans (Pongo Pygmaeus Abelii Lesson 1827). Ecology, behaviour and conservation.
Description: Wageningen, 1976. Original wraps., (4), 420pp., 161 text-ills., figures, sketch-maps, tables, graphs, references (bibliography), appendices, summaries in English, Dutch & Bahasa. Meded. Landbouwhogeschool Wageningen.. 78-2 (1978).

Keywords: Sumatra/orang utan