Abid, Muhammad, Nasir Abbas, Rehan Ahmad Khan sherwani, and Hafiz Zafar Nazir. 2016. “Improved Ratio Estimators for the Population Mean Using Non-Conventional Measures of Dispersion”. Pakistan Journal of Statistics and Operation Research 12 (2), 353-67. https://doi.org/10.18187/pjsor.v12i2.1182.