Soil conservation. assessing the national resources inventory / Vol. 1 :

Manylion Llyfryddiaeth
Awdur Corfforaethol:	National Research Council (U.S.). Board on Agriculture. Committee on Conservation Needs and Opportunities
Fformat:	Licensed eBooks
Iaith:	Saesneg
Cyhoeddwyd:	Washington, D.C. : National Academy Press, 1986.
Mynediad Ar-lein:	https://search.ebscohost.com/login.aspx?direct=true&scope=site&db=nlebk&AN=15903

Rhyngrwyd