Rilwan, U., et al. “Radiometric Evaluation Naturally Occurring Radionuclides in Some Ongoing Drilled Boreholes across Keffi Town of Nasarawa State, Nigeria”. International Astronomy and Astrophysics Research Journal, vol. 1, no. 1, Jan. 2020, pp. 58-66, doi:10.9734/iaarj/2019/v1i18.