http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Field crop fertilization on Texas Blackland and Grand Prairie soils
Charles D. Welch, Carl Gray, George D. Alston and Billy W. Hipp.
The United States Department of Agriculture cooperating.
L (Texas Agricultural Extension Service) ; 743 [1980 revision]