T. Simorangkir

Orangutan distribution, density, abundance and impacts of disturbance

Serge A. Wich, Andrew J. Marshall, Andrew J. Hearn, 2009 .

Distribution and conservation status of the orang-utan (Pongo spp.) on Borneo and Sumatra: how many remain?

Serge A. Wich, Robert C. Lacy, Andrew J. Marshall, 2008, Oryx.