A.A, El-Sheikh, and El-Kossaly H. A. “Calibration Estimation for Ratio Estimators in Stratified Sampling for Proportion Allocation”. Journal of Progressive Research in Mathematics 16, no. 4 (October 8, 2020): 3199-3205. Accessed May 1, 2024. http://www.scitecresearch.com/journals/index.php/jprm/article/view/1924.