Elhassan, A. M., A. M. Babiker, M. E. Ahmed, and A. M. El Hussein. “Coinfections of Sudanese Dairy Cattle With Bovine Herpes Virus 1, Bovine Viral Diarrhea Virus, Bluetongue Virus and Bovine Herpes Virus 4 and Their Relation to Reproductive Disorders”. Journal of Advanced Veterinary and Animal Research, vol. 3, no. 4, Feb. 2017, pp. 332-7, https://banglajol.info/index.php/JAVAR/article/view/31511.