Kock, N.D.; Jongejan, F.; Kock, M.D.; Kock, R.; Morkel, P. 1992. Serological evidence of Cowdria ruminantium infection in free-ranging black (Diceros bicornis) and white (Ceratotherium simum) rhinoceroses in Zimbabwe.
Journal of Zoo and Wildlife Medicine 23 (4): 409-413, table 1.