Joshi, P. K.; Jha, A. K.; Wani, Suhas P.; Joshi, Laxmi; Shiyani, R. L.(Comprehensive Assessment of Water Management in Agriculture, Colombo, Sri Lanka, 2005)
Hoagland, Porter; Kaoru, Yoshiaki; Broadus, James M.(Pollution and Environmental Economics Division, Environment Department, World Bank, Washington, DC, 1995)