Soil survey staff. (1990). Keys to soil taxonomy. Blacksburg, Va: Virginia Polytechnic Institute and State University.
Chicago Stili AlıntıSoil survey staff. Keys to Soil Taxonomy. Blacksburg, Va: Virginia Polytechnic Institute and State University, 1990.
MLA AlıntıSoil survey staff. Keys to Soil Taxonomy. Blacksburg, Va: Virginia Polytechnic Institute and State University, 1990.
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