United States. Forest Service. Northern Region & Ford, G. L. (1997). Landtype associations of the northern region, a first approximation. USDA Forest Service.
Chicago Style (17th ed.) CitationUnited States. Forest Service. Northern Region and Gary L. Ford. Landtype Associations of the Northern Region, a First Approximation. [Washington, D.C.?]: USDA Forest Service, 1997.
MLA (9th ed.) CitationUnited States. Forest Service. Northern Region and Gary L. Ford. Landtype Associations of the Northern Region, a First Approximation. USDA Forest Service, 1997.
Warning: These citations may not always be 100% accurate.