BLOODLESS DZWAIRO; FREDRICK AO OTIENO. Class frequency distribution for a surface raw water quality index in the Vaal Basin. Water SA, [S. l.], v. 40, n. 2 April, 2025. DOI: 10.4314/wsa.v40i2.16. Disponível em: https://watersa.net/article/view/21769. Acesso em: 1 may. 2025.