Bayu, T., and S. Genanu. “A Contingent Valuation Approach to Household’s Willingness to Pay for Improved Piped Water Access in North Wollo Zone, Ethiopia”. Ethiopian Journal of Economics, vol. 33, no. 2, May 2026, pp. 63-97, https://www.ajol.info/index.php/eje/article/view/324092.