1. Adenike AA, Titus OB (2009) Determinants of WTP extra for improved water supply in Osogbo Metropolis; Osun State, Nigeria. Res J Soc Sci 4:1–6
2. Ahmad I, Sattar A (2010) Factors determining public demand for safe drinking water (A Case Study of District Peshawar). PIDE Working Papers: 58
3. Bartlett JE, Kotrlik JW, Higgins CC (2001) Organizational research: determining appropriate sample size in survey research. Inform Technol Learn Perform J 19(1):43–50
4. Behailu S, Kume A, Desalegn B (2012) Household’s WTP extra for improved water service: a case study in Shebedino District. South Ethiop Water Environ J 26(3):429–434
5. Briscoe J (1996) Water as an Economic Good: The Idea and What it Means in Practice. Proceedings of the ICID World Congress. Cairo, Egypt