Ponkaew, C., and N. Lawson. “ESTIMATING VARIANCE IN THE PRESENCE OF NONRESPONSE UNDER UNEQUAL PROBABILITY SAMPLING WITHOUT REPLACEMENT”. Suranaree Journal of Science and Technology, vol. 26, no. 3, Aug. 2026, pp. 293-02, https://ph04.tci-thaijo.org/index.php/SUJST/article/view/14661.