Sexual isolation between two sibling species with overlapping ranges: Drosophila santomea and Drosophila yakuba.
Coyne JA, Kim SY, Chang AS, Lachaise D, Elwyn S. Sexual isolation between two sibling species with overlapping ranges: Drosophila santomea and Drosophila yakuba. Evolution. 2002 Dec; 56(12):2424-34.