1. Drain-spacing formula;Dumm;Agr. Eng.,1954
2. Transient flow concept in subsurface drainage: Its validity and use;Dumm;Trans. ASAE,1964
3. A study of non-steady groundwater flow with special reference to a reservoir-coefficient;Kraijenhoff van de Leur;Ingenieur: The Hague,1958
4. Kramer , D. E. Field comparisons of hydraulic conductivity methods and drainage envelope hydraulic characteristics Brookings 1974