& et al., M. 2020. EFFECT OF ADDING PENTOXIFYLLINE AND NITRIC OXIDE TO TRIS EXTENDER ON SOME POST-CRYOPRESERVED SEMEN ATTRIBUTES OF HOLSTEIN BULLS. IRAQI JOURNAL OF AGRICULTURAL SCIENCES. 51, 2 (Apr. 2020), 619–628. DOI:https://doi.org/10.36103/ijas.v51i2.989.