Abdullahi, M. G.; Kamarudin, M. K. A.; Umar, R.; Endut, A.; Khalit, S. I.; Juahir, H. Night Sky Brightness Assessment in Nigeria Using Environmetric and GIS Technique. Int. J. Adv. Sci. Eng. Inf. Technol. 2017, 7, 28-34.