Macacasilenus in der Roten Liste gefährdeter Arten der IUCN 2006. Eingestellt von: Participants of CBSG CAMP workshop: Status of South Asian Primates (March 2002), 2004. Abgerufen am 23. Juli 2011.
sciencedirect.com
M. Balakrishnan: The larger mammals and their endangered habitats in the silent valley forests of South India. Biological Conservation Volume 29, Issue 3, 1984, S. 277–286. online abstract-online PDF.
M. Balakrishnan: The larger mammals and their endangered habitats in the silent valley forests of South India. Biological Conservation Volume 29, Issue 3, 1984, S. 277–286. online abstract-online PDF.
web.archive.org
Joseph, Gigi K., & Ramachandran, K.K. (2003). Distribution and Demography of the Nilgiri Langur (Trachypithecus johnii) in Silent Valley National Park and Adjacent Areas, Kerala, India. Primate Conservation, volume 19, S. 78–82. IUCN/SSC Primate Specialist Group PDF (Memento vom 28. September 2007 im Internet Archive).