Otobo G, Endurance Fegor Isoje, Augustina Ufuoma Igbuku. Hazardous Nature of Native Chalk (Calabash chalk). IJSBAR. 2023;71(1):31-36. Accessed January 11, 2026. https://www.gssrr.org/JournalOfBasicAndApplied/article/view/16177