a framework for international classification, correlation, and communication Food and Agriculture Organization of the United Nations text Rome Food and Agriculture Organization of the United Nations 2006 2006 ed. monographic ix, 128 p. ; 30 cm. Soils 631 FOO 2006 A036 Or. 9251055114 http://www.loc.gov/catdir/toc/fy0710/2006484408.html http://www.fao.org/AG/AGL/agll/wrb/doc/wrb2006final.pdf http://www.loc.gov/catdir/toc/fy0710/2006484408.html http://www.fao.org/AG/AGL/agll/wrb/doc/wrb2006final.pdf