Genetic variation of porcine prostaglandin-endoperoxide synthase 2 (PTGS2) gene and its association with reproductive traits in an Erhualian X Duroc F2 population - Ding, N.-S.; Ren, D.-R.; Guo, Y.-M.; Ren, J.; Yan, Y.; Ma, J.-W.; Chen, Kefei; Huang, L.-S. (Kexue Chubaneshe/Science Press, 2006)