J. O. Muili, R. V. K. Singh, G. I. Onwuka, and A. Audu, “NEW CALIBRATION OF FINITE POPULATION MEAN OF COMBINED RATIO ESTIMATORS IN STRATIFIED RANDOM SAMPLING”, FJS, vol. 6, no. 4, pp. 37–44, Aug. 2022, doi: 10.33003/fjs-2022-0604-920.