1. Allen, R.G., L.S. Pereira, D. Raes, and M. Smith. 1998. Crop evapotranspiration (guidelines for computing crop water requirements). Food and Agricultural Organization Irrigation and Drainage Paper 56, accessible online at:
http://www.fao.org/docrep/X0490E/X0490E00.htm
.
2. Amarasingha, R.P.R.K., L.W. Galagedara, B. Maramabe, G.L.L.P. Silva, R. Punyawardena, U. Nidumolu, M. Howden, and L.D.B. Suriyagoda. 2014. Aligning sowing dates with the onset of rains to improve rice yields and water productivity: Modeling rice (Oryza sativa L.) yield of the Maha season in the dry zone of Sri Lanka. Tropical Agricultural Research 25: 277–284.
3. Bos, M.G., R.A. Kselik, R.G. Allen, and D. Molden. 2008. Water requirements for irrigation and the environment. Dordrecht: Springer Science & Business Media.
4. Bouman, B., R. Barker, E. Humphreys, and T. P. Tuong. 2007. Rice: Feeding the billions. In Water for Food, Water for Life: A Comprehensive Assessment of Water Management, chap. 14, pp. 515–549. Colombo: International Water Management Institute.
5. Brouwer, C., and M. Heibloem. 1986. Irrigation water management: Irrigation water needs. In Irrigation Water Management: Irrigation Water Needs, Training manual no. 3, pp. 63–70. Rome: Food and Agricultural Organization of the United Nations.