Suwardi (2020) “Design & Calculation of Radiation Retaining Wall Thickness Cobalt-60 Source of Brachytherapy at Radiotherapy Unit Dr. Kariadi Hospital Semarang”, International Journal of Allied Medical Sciences and Clinical Research, 7(3), pp. 835–840. doi: 10.61096/ijamscr.v7.iss3.2019.835-840.