Pennant's colobus (English Wikipedia)

Jimenez, Mariano II; Jiménez, Mariano G. (2004). "El Colobo Rojo de Pennant (Procolobus pennantii)". El Zoológico Electrónico: Mamíferos: Primates: Monos del Viejo Mundo. Damisela. Retrieved 2013-09-03.

doi.org (Global: 2^nd place; English: 2^nd place)

Cronin, D.T. (2019). "Piliocolobus pennantii". IUCN Red List of Threatened Species. 2019 e.T41025A92653653. doi:10.2305/IUCN.UK.2019-3.RLTS.T41025A92653653.en. Retrieved 12 November 2021.
Struhsaker, Thomas T. (1995). "Colobine monkeys: Their ecology, behaviour and evolution". International Journal of Primatology. 16 (6): 1035–1037. doi:10.1007/BF02696118. S2CID 31026977.
Ikemeh, R.; Oates, J.F.; Inaoyom, I. (2019). "Piliocolobus epieni". IUCN Red List of Threatened Species. 2019 e.T41024A92656391. doi:10.2305/IUCN.UK.2019-3.RLTS.T41024A92656391.en. Retrieved 12 November 2021.
Maisels, F.; Devreese, L. (2020). "Piliocolobus bouvieri". IUCN Red List of Threatened Species. 2020 e.T18250A166600357. doi:10.2305/IUCN.UK.2020-1.RLTS.T18250A166600357.en. Retrieved 12 November 2021.

Mittermeier, R.A.; Wallis, J.; Rylands, A.B.; Ganzhorn, J.U.; Oates, J.F.; Williamson, E.A.; Palacios, E.; Heymann, E.W.; Kierulff, M.C.M.; Long Yongcheng; Supriatna, J.; Roos, C.; Walker, S.; Cortés-Ortiz, L.; Schwitzer, C., eds. (2009). Primates in Peril: The World's 25 Most Endangered Primates 2008–2010 (PDF). Arlington, VA.: IUCN/SSC Primate Specialist Group (PSG), International Primatological Society (IPS), and Conservation International (CI). pp. 1–92. ISBN 978-1-934151-34-1. Archived from the original (PDF) on 2011-07-23. Retrieved 2010-08-07.

Struhsaker, Thomas T. (1995). "Colobine monkeys: Their ecology, behaviour and evolution". International Journal of Primatology. 16 (6): 1035–1037. doi:10.1007/BF02696118. S2CID 31026977.

Mittermeier, R.A.; Wallis, J.; Rylands, A.B.; Ganzhorn, J.U.; Oates, J.F.; Williamson, E.A.; Palacios, E.; Heymann, E.W.; Kierulff, M.C.M.; Long Yongcheng; Supriatna, J.; Roos, C.; Walker, S.; Cortés-Ortiz, L.; Schwitzer, C., eds. (2009). Primates in Peril: The World's 25 Most Endangered Primates 2008–2010 (PDF). Arlington, VA.: IUCN/SSC Primate Specialist Group (PSG), International Primatological Society (IPS), and Conservation International (CI). pp. 1–92. ISBN 978-1-934151-34-1. Archived from the original (PDF) on 2011-07-23. Retrieved 2010-08-07.
Groves, C. (2007). "The taxonomic diversity of the Colobinae of Africa" (PDF). Journal of Anthropological Sciences. 85: 7–34. Archived from the original (PDF) on 2013-05-14.
Pennant's red colobus Archived 2008-07-25 at the Wayback Machine. ARKive. Accessed 2013-09-03