M. A. Nuriman, M. B. C. Khoo, S. Saha, Z. L. Chong, and S. Chua, “Performance of the Double Sampling Coefficient of Variation Chart under Measurement Errors Using a Linear Covariate Error Model for Monitoring NPK Fertilizer Manufacturing Process”, JQMA, vol. 22, no. 1, pp. 173–204, Mar. 2026.