Antony, J. (2018) “Willingness to Pay for Access to Improved and Reliable Piped Water: A Contingent Valuation Study in Kerala, India”, Thailand Statistician, 17(1), pp. 75–83. available at: https://ph02.tci-thaijo.org/index.php/thaistat/article/view/163198 (accessed: 17 September 2026).