Defective mammopoiesis, but normal hematopoiesis, in mice with a targeted disruption of the prolactin gene - Horseman, N D; Zhao, W; Montecino-Rodriguez, E; Tanaka, M; Nakashima, K; Engle, S J; Smith, F; Markoff, E; Dorshkind, K (EMBO J, 1997)