United States. Bureau of Soils. (1912). Occurrence and nature of carbonized materials in soils. GPO.
Chicago Style (17th ed.) CitationUnited States. Bureau of Soils. Occurrence and Nature of Carbonized Materials in Soils. [Washington]: GPO, 1912.
MLA (9th ed.) CitationUnited States. Bureau of Soils. Occurrence and Nature of Carbonized Materials in Soils. GPO, 1912.
Warning: These citations may not always be 100% accurate.