Egor, A. O., Ushie, J. A., & Abong, A. A. (2026). Geological Determinants of Indoor Radon-222 Levels in Residential Buildings: A Case Study of Cross River State, Southeastern Nigeria. Nigerian Journal of Physics, 35(3), 274-283. https://doi.org/10.62292/njp.v35i3.2026.597