Brooks, Kenneth N.; Ffolliott, Peter F.; Gergersen, Hans M.; Easter, K. William(The Environmental and Natural Resources Policy and Training Project, University of Wisconsin-Madison, Madison, WI, 1994)
Amerasinghe, Felix P.; Konradsen, Flemming; Van Der Hoek, Wim; Amerasinghe, Priyanie H.; Gunawardena, J. P. W.; Fonseka, K. T.; Jayasinghe, Gayathri(International Water Management Institute (IWMI), Colombo, Sri Lanka, 2001)