Emtairah, Tareq; Echavarria, Marta; Hamann, Ralph(United Nations Environment Programme Finance Initiative (UNEP FI); Stockholm International Water Institute (SIWI), Sweden, 2005)
Somaratne, P. G.; Jinapala, K.; Perera, L. R.; Ariyaratne, B. Ranjith; Bandaragoda, D. J.; Makin, Ian(International Water Management Institute, Colombo, Sri Lanka, 2003)