Thakur, N. S. ., K. . Yadav, and S. . Pathak. “IMPUTATION USING REGRESSION ESTIMATORS FOR ESTIMATING POPULATION MEAN IN TWO-PHASE SAMPLING”. Journal of Reliability and Statistical Studies, vol. 5, no. 02, Dec. 2012, pp. 21-31, https://journals.riverpublishers.com/index.php/JRSS/article/view/21907.