Garrison, G.A.; Bjusgstad, A.J.; Duncan, D.A.; Lewis, M.E.; Smith, D.R. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, D.C.: U.S. Department of Agriculture, Forest Service. 68 p.

Garrison, G.A.; Bjusgstad, A.J.; Duncan, D.A.; Lewis, M.E.; Smith, D.R. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, D.C.: U.S. Department of Agriculture, Forest Service. 68 p.