United States Department of Agriculture, & Natural Resources Conservation Service. (1995). Soil survey laboratory information manual. Lincoln: National Soil Survey Center.
Παραπομπή Chicago StyleUnited States Department of Agriculture, και Natural Resources Conservation Service. Soil Survey Laboratory Information Manual. Lincoln: National Soil Survey Center, 1995.
Παραπομπή MLAUnited States Department of Agriculture, και Natural Resources Conservation Service. Soil Survey Laboratory Information Manual. Lincoln: National Soil Survey Center, 1995.
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