OTOBO, Grace; ENDURANCE FEGOR ISOJE; AUGUSTINA UFUOMA IGBUKU. Hazardous Nature of Native Chalk (Calabash chalk). International Journal of Sciences: Basic and Applied Research (IJSBAR), Jordan, v. 71, n. 1, p. 31–36, 2023. Disponível em: https://www.gssrr.org/JournalOfBasicAndApplied/article/view/16177. Acesso em: 17 sep. 2025.