Soil Survey of Clackamas County Area, Oregon Allen J. Gerig Published: 1985 Total Pages: 402 Get eBook
Soil Survey of Polk County, Oregon United States. Bureau of Soils Published: 1927 Total Pages: 60 Get eBook
Index to Publications of the United States Department of Agriculture, 1926-1930 United States. Department of Agriculture. Division of Publications Published: 1935 Total Pages: 712 Get eBook
