C.  Laing, Carmody, G. R., and PECK, S. B., ?Population genetics and evolutionary biology of the cave beetle Ptomaphagus hirtus?, Evolution, vol. 30, pp. 484-498., 1976.

S. B.  PECK, ?Evolution of adult morphology and life-history characters in cavernicolous Ptomaphagus beetles?, Evolution, vol. 40, pp. 1021-1030., 1986.