Vermillion, Douglas L.; Samad, Madar; Pusposutardjo, Suprodjo; Arif, Sigit S.; Rochdyanto, Saiful(International Water Management Institute (IWMI), Colombo, Sri Lanka, 2000)
Molle, François; Jayakody, Priyantha; Ariyaratne, B. Ranjith; Somatilake, H. S.(International Water Management Institute (IWMI), Colombo, Sri Lanka, 2005)
Theesfeld, Insa; Boevsky, Ivan(Central and Eastern European Sustainable Agriculture (CEESA), Humboldt University of Berlin, Department of Agricultural Economics and Social Sciences, Berlin, Germany, 2003)