Smith, G.M. 1950. The Fresh-Water Algae of The United States. McGraw-Hill Book Company, New York. 



Stevenson, R.J., and Y. Pan. 1999. Assessing Environmental Conditions in Rivers and Streams with 

 Diatoms. Chapter 2 in Stoermer, E.F., and J. P. Smol (eds.), The Diatoms: Applications For the 

 Environmental and Earth Sciences, Cambridge University Press, New York. 



Stewart, W.D.P., P. Rowell, and A.N. Rai. 1980. Symbiotic Nitrogen-Fixing Cyanobacteria. Pp. 239-277 in 

 Stewart, W.D.P., and J. Gallo (eds.). Nitrogen Fixation, Academic Press, New York. 



USDA. 1976. Climax Vegetation of Montana (map). U.S. Department of Agriculture, Soil Conservation Service, 

 Cartographic Unit, Portland. 



USEPA. 2000. Level III Ecoregions of the Continental United States (map). National Health and Environmental 

 Effects Research Laboratory, U.S. Environmental Protection Agency, Corvallis, Oregon. 



Van Dam, Herman, Adrienne Mertens, and Jos Sinkeldam. 1994. A coded checklist and ecological Indicator values 

 of freshwater diatoms from The Netherlands. Netherlands Journal of Aquatic Ecology 28(1):1 17-133. 



Weber, C.l. (ed.). 1973. Biological Field and Laboratory Methods for Measuring the Quality of Surface 

 Waters and Effluents. EPA-670/4-73-001. U.S. Environmental Protection Agency, National 

 Environmental Research Center, Office of Research and Development, Cincinnati, Ohio. 



Wehr, J. D., and R.G. Sheath. 2003. Freshwater Algae of North America: Ecology and Classification. Academic 

 Press, New York. 



Whittaker, R.H. 1952. A study of summer foliage insect communities in the Great Smoky Mountains. 

 Ecological Monographs 22:1-44. 



Woods, A. J., Omemik, J.M., Nesser, J. A., Shelden, J., and S.H. Azevedo. 1999. Ecoregions of Montana (color 

 poster with map), U.S. Geological Survey, Reston, Virginia. 



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