J. A. Bishop, An Experimental Study of the Cline of Industrial Melanism in Biston betularia (L.) (Lepidoptera) between Urban Liverpool and Rural North Wales, Journal of Animal Ecology, Vol. 41, No. 1 (Feb., 1972), pp. 209-243
No takes yet. Share an insight, caveat, or question.
J. A. Bishop (1972) studied this question.