United States Department of Agriculture, & Natural Resources Conservation Service. (1995). Soil survey laboratory information manual. Lincoln: National Soil Survey Center.
Chicago Style aipamenaUnited States Department of Agriculture, và Natural Resources Conservation Service. Soil Survey Laboratory Information Manual. Lincoln: National Soil Survey Center, 1995.
MLA aipamenaUnited States Department of Agriculture, và Natural Resources Conservation Service. Soil Survey Laboratory Information Manual. Lincoln: National Soil Survey Center, 1995.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.