Pristiwanto, P., Heri Sunandar, and Berto Nadeak. “Analysis and Implementation of PlayFair Chipper Algorithm in Text Data Encoding Process”. Jurnal Info Sains : Informatika Dan Sains, vol. 10, no. 2, Sept. 2020, pp. 19-23, doi:10.54209/infosains.v10i2.33.