H. P. Ritzema, Drainage principles and applications, 2nd rev. ed.nd ed., vol. no. 16. Wageningen, The Netherlands: International Institute for Land Reclamation and Improvement, 1994, p. 1125 p. : fig., tab.
1980
A. Breuer and Netzband, A., “Small scale irrigation”. German Appropriate Technology Exchange (GATE) /Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ), Eschborn, Germany, p. 97 p. : fig. tab., 1980.