3) ALFONSO, L., J.L. NOGUERA, D. BABOT and J. ESTANY : Estimates of genetic parameters for litter size at different parities in pigs, Livest. Prod. Sci., 47, 149-156, 1997.
4) SERENIUS, T., M.-L. SEVON-AIMÓNEN, A. KAUSE, E.A. MÄNTYSAARI and A. MÄKI-TANILA : Selection potential of different prolificacy traits in the Finnish Landrace and Large White populations, Acta Agric. Scand., 54, 36-43, 2004.