1. A new soil core sampler;Powell;Soil Sci.,1926
2. The San Dimas soil core sampler;Andrews;Soil Sci.,1958
3. Core samplers for soil profiles;Wells;J. agric. Engng Res.,1959
4. A soil sampling machine for obtaining two, three and fourinch diameter cores of undisturbed soil to a depth of six feet;Kelley;Soil Sci. Soc. Am. Proc.,1947
5. A description and comments on a power-driven soil profile core sampler;Wells,1959