United States Department of Agriculture, & Natural Resources Conservation Service. (1996). Soil survey methods manual: The soil survey analytical continuum. Lincoln: National Soil Survey Center.
Dyfyniad Arddull ChicagoUnited States Department of Agriculture, và Natural Resources Conservation Service. Soil Survey Methods Manual: The Soil Survey Analytical Continuum. Lincoln: National Soil Survey Center, 1996.
Dyfyniad MLAUnited States Department of Agriculture, và Natural Resources Conservation Service. Soil Survey Methods Manual: The Soil Survey Analytical Continuum. Lincoln: National Soil Survey Center, 1996.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.