Knight, M., P. Hitchins, and K. Erb. “An Aerial Survey of Rhinoceros and Elephant in a Portion of the Chobe National Park and Surrounding Areas, Northern Botswana, September 1992”. Pachyderm, vol. 17, no. 1, Dec. 1993, pp. 64-74, doi:10.69649/pachyderm.v17i1.785.