KHAN, Lakhkar; JAVID SHABBIR; QAZI UBAID; TAJ FARIN KHAN. A Refinement of Ratio Estimation in Ranked Set Sampling and Stratified Ranked Set Sampling Approaches. VFAST Transactions on Mathematics, [S. l.], v. 12, n. 1, p. 30–45, 2024. DOI: 10.21015/vtm.v12i1.1619. Disponível em: https://vfast.org/journals/index.php/VTM/article/view/1619. Acesso em: 28 apr. 2026.