Abdullah, Ahmed Rushdi, et al. “Increasing Serum Level of Transforming Growth Factor Beta 2 (TGF-β) in Patients With Colorectal and Gastric Cancer in Iraq”. Journal of Biotechnology Research Center, vol. 7, no. 1, Jan. 2013, pp. 72-79, doi:10.24126/jobrc.2013.7.1.249.