@misc{Sawa_Anna_Effect, author={Sawa, Anna and Jankowska, Małgorzata and Neja, Wojciech and Krężel-Czopek, Sylwia}, howpublished={online}, publisher={Instytut Zootechniki Państwowy Instytut Badawczy}, language={eng}, type={artykuł}, title={Effect of single and multiple pregnancies and calf sex on parturition process and perinatal mortality}, keywords={calf, cattle, perinatal mortality, twin}, }