Cloning and expression of a distinctive class of self-incompatibility (S) gene from Papaver rhoeas L. - Foote, ,H..C. C.,.; Ride, ,J..P.,.; Franklin-Tong, ,V..E.,.; Walker, ,E..A.,.; Lawrence, ,M..J.,.; and Franklin, ,F..C. H.. (Proc. Natl. Acad. Sci. USA, 1994)