Theory and speciation
M. Turelli, N.H. Barton, J. Coyne, Trends in Ecology and Evolution 16 (2001) 330–343.

Hybrids and hybrid zones: Reply from M.G. Ritchie and N.H. Barton
M. Ritchie, N.H. Barton, Trends in Ecology and Evolution 13 (1998) 282–283.