Oates, J.; Sunderland-Groves, J.; Bergl, R.; Dunn, A.; Nicholas, A.; Takang, E.; Omeni, F.; Imong, I.; Fotso, R.; Nkembi, L.; Williamson, E. A. (2007). "Regional Action Plan for the Conservation of the Cross River Gorilla (Gorilla gorilla diehli)"(PDF). IUCN/SSC Primate Specialist Group and Conservation International, Arlington, VA, USA. Diarsipkan(PDF) dari versi asli tanggal 2013-10-22. Diakses tanggal 21 October 2013.
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Oates, J.; Sunderland-Groves, J.; Bergl, R.; Dunn, A.; Nicholas, A.; Takang, E.; Omeni, F.; Imong, I.; Fotso, R.; Nkembi, L.; Williamson, E. A. (2007). "Regional Action Plan for the Conservation of the Cross River Gorilla (Gorilla gorilla diehli)"(PDF). IUCN/SSC Primate Specialist Group and Conservation International, Arlington, VA, USA. Diarsipkan(PDF) dari versi asli tanggal 2013-10-22. Diakses tanggal 21 October 2013.