Sys, C., Van Ranst, E., Debaveye, J. and Beerneaert, F.1993. Land evaluation: Part III: Crop requirements.
Development Cooperation, Belgium.
Naidu, L.G.K., Ramamurthy, V., Challa O., Hegde, R. and Krishnan, P. 2006. Manual, Soil-site Suitability Criteria for Major Crops, National Bureau of Soil Survey and Land Use Planning, ICAR, Nagpur, India
FAO Crop Suitability Requirements: http://ecocrop.fao.org/ecocrop/srv/en/home