O'BRIEN, S. J., J. S. MARTENSON, M. A. EICHELBERGER, E. T. THORNE, AND F. WRIGHT. 1989. Genetic variation and molecular systematics of the black-footed ferret, P. 209 in Conservation Biology and the Biology of the Black-Footed Ferret (U. S. Seal, E. T. Thorne, M. A. Bogan and S. H. Anderson, eds.). Yale University Press, New Haven and London.