The ... yearbook of agriculture [elektronický zdroj]. Washington, D.C. : U.S. Dept. of Agriculture : For sale by the Supt. of Docs., U.S. G.P.O., [1980-1993]. 13 v. Available on Internet: <http://sfx.jib.cz/sfxlcl3?url_ver=Z39.88-2004&ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&rfr_id=info:sid/sfxit.com:opac_856&url_ctx_fmt=info:ofi/fmt:kev:mtx:ctx&sfx.ignore_date_threshold=1&rft.object_id=991042729620742&svc_val_fmt=info:ofi/fmt:kev:mtx:sch_svc&>