LAWAN BULAMA, et al. “ASSESSING THE EFFECTIVENESS OF SPI AND PDBM INDICES IN METEOROLOGICAL DROUGHTS DETECTION; A COMPARATIVE APPROACH”. International Journal of Advanced Academic Research, vol. 9, no. 11, Nov. 2023, pp. 1-11, https://www.openjournals.ijaar.org/index.php/ijaar/article/view/254.