Chhaparwal, Priyanka, and Sanjay Kumar. “Improving Efficiencies of Ratio- and Product-Type Estimators for Estimating Population Mean for Time-Based Survey”. Journal of Reliability and Statistical Studies 15, no. 01 (April 29, 2022): 325–340. Accessed May 19, 2024. https://journals.riverpublishers.com/index.php/JRSS/article/view/20323.