1. Soil series and drainage practices;Armstrong;FDEU Tech. Bull.,1977
2. Improving the design of practical field drainage;Trafford;Soil Sci.,1976
3. Drainage Principles and Applications;International Institute for Land Reclamation and Improvement,1973
4. Transient design of drainage systems;van Schilfgaarde,1965
5. Graphical solution and interpretation of a new drain-spacing formula;Toksöz;J. geophys. Res.,1961