O. M. Olayiwola, F. S. Apantaku, K. A. Oyekunle, A. A. Akintunde, O. A. Wale-Orojo, and S. A. Olawoore, “A MODIFIED CALIBRATION APPROACH FOR RATIO ESTIMATOR IN STRATIFIED SAMPLING”, FJS, vol. 4, no. 4, pp. 507–512, Jun. 2021, doi: 10.33003/fjs-2020-0404-510.