Perera, A. P. D. N.; Malagala, D. K. M.; Rasanjalee, M.; Pathirana, P. T.; Ranathunga, R. R. A. L. W.
(Journal of Social Statistics (JSS – 2019), Volume 06, Issue 01. Department of Social Statistics, Faculty of Social Sciences, University of Kelaniya, Sri Lanka, 2019)