Rodin, L. E., N. I. Bazilevich and N. N. Rozov. 1972. Productivity of the 

 world's main ecosystems. Pages 13-26, in Productivity of World 

 Ecosystems. National Academy of Sciences, Washington, DC. 



Sculthorpe, C. D. 1967. The Biology of Aquatic Vascular Plants. St. Martin's 

 Press, Garden City, NJ. 



Spencer, H. E., Jr. 1963. Man-made marshes for Maine waterfowl. Game Div. 

 Bull. No. 9. Maine Department of Inland Fisheries and Wildlife, (formerly 

 Maine Department of Inland Fisheries and Game) , Augusta , ME. 



Swanson, G. A., M. I. Meyer, and J. R. Serie. 1974. Feeding ecology of 

 breeding blue-winged teals. J. Wildl. Manage. 38(3) : 396-407 . 



Westlake, D. F. 1963. Comparisons of plant productivity. Biol. Rev. 38:385- 

 425. 



Wetzel, R. G. 1975. Limnology. W. B. Saunders, Philadelphia. 



8-34 



10-80 



