(1999). 1997 census of agriculture. [Washington, D.C.]: U.S. Dept. of Agriculture, National Agricultural Statistics Services.
Dyfyniad Arddull Chicago1997 Census of Agriculture. [Washington, D.C.]: U.S. Dept. of Agriculture, National Agricultural Statistics Services, 1999.
Dyfyniad MLA1997 Census of Agriculture. [Washington, D.C.]: U.S. Dept. of Agriculture, National Agricultural Statistics Services, 1999.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.