Sanz, A., Bernués, A., Casasús, I., Villalba, D. and Revilla, R. (2003) “Management factors associated to the duration of postpartum anoestrus interval in Brown Swiss and Pirenaica beef cows”, Spanish Journal of Agricultural Research, 1(1), pp. 7-21. doi: 10.5424/sjar/2003011-5.