Hapuhinna, H. K. D. W. M. S. K.; Kumar, S.(5th National Conference on Applied Social Statistics (NRCASS) - 2019, Department of Social Statistics, Faculty of Social Sciences, University of Kelaniya, Sri Lanka, 2019)
Ubesekara, K. K. S. U.I.(Journal of Social Statistics (JSS – 2019), Volume 06, Issue 01. Department of Social Statistics, Faculty of Social Sciences, University of Kelaniya, Sri Lanka, 2019)