Mallon, D., Kümpel, N., Quinn, A., Shurter, S., Lukas, J., Hart, J.A., Mapilanga, J., Beyers, R. & Maisels, F. 2015. Okapia johnstoni. The IUCN Red List of Threatened Species 2015: e.T15188A51140517. https://doi.org/10.2305/IUCN.UK.2015-4.RLTS.T15188A51140517.en. Downloaded on 09 January 2021.
Richard E. Bodmer, George B. Rabb, "Okapia johnstoni," Mammalian Species, No. 422, American Society of Mammalogists, 1992, Pages 1 - 8.
