Dery, T., J. Amoako, P. Buah-Bassuah, and W. Osei-Mensah. “Virtual Simulation of Co-60 Gamma Ray Beam Geometry”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 38, no. 2, May 2018, pp. 116-22, https://www.gssrr.org/index.php/JournalOfBasicAndApplied/article/view/8886.