G. N. SINGH; A. K. SHARMA. An Improved Estimation Procedure of Population Mean in Two Phase Sampling. Journal of International Academy of Physical Sciences, [S. l.], v. 18, n. 1, p. 01–10, 2014. Disponível em: https://www.iaps.org.in/journal/index.php/journaliaps/article/view/462. Acesso em: 18 may. 2024.