1. Soil management to reduce runoff under center-pivot sprinkler systems;Aarstad;J. Soil Water Conserv.,1973
2. Beck, R. D., Phene, C. J., and Soenke, S. D. (1980). An electronic control system for a traveling trickle irrigation system (TTIS). Proc. Electro-Opt./Laser Conf. Exp. Boston, Nov. 19–21. pp. 9–15.
3. Semicrystalline cells see steep price drop;Berney;Electronics,1983
4. Subsurface irrigation;Blass;Hassadeh,1964
5. Bray, R. E. (1979). Solar-climate statistical study. Summary Report, Vol. 1, U.S. Dept. of Energy HCP/T-4016/1.