Wolf, K. N., Wildt, David E., Vargas, A., Marinari, Paul E., Kreeger, J. S., Ottinger, M. A., and Howard, JoGayle. 2000. "
Age dependent changes in sperm production, semen quality and testicular volume in the black-footed ferret (Mustela nigripes)."
Biology of Reproduction, 63 179–187.