1. Amer. Soc. Agr. Eng. (1967) Tillage for greater crop production. Conf. Proc. ASAE, Publ. PROC-168 St. Joseph, Mich.
2. A diffusion and mass-flow concept of soil nutrient availability;Barber;Soil Sci.,1962
3. Fertilizer use on corn;Barber,1968
4. Mechanisms for the movement of plant nutrients from the soil and fertilizer to the plant root;Barber;J. Agr. Food Chem.,1963
5. The configuration of the root system in relation to nutrient uptake;Barley;Advan. Agron.,1970