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Barinaga, M.  1990.  Where have all the froggies gone?  Science 247:1033-1034.

Bishop, C. A., K. E. Pettit, M. E. Gartshore, and D. A. MacLeod.  1996.  
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Blaustein, A. R.  1994.  Chicken Little or Nero's fiddle?  A perspective on 
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Blaustein, A. R. and D. B. Wake.  1990.  Declining amphibian populations: a 
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Bluemle, J. P.  1991.  The face of North Dakota, revised edition.  North Dakota 
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Bowers, D. G., D. E. Andersen, and N. H. Euliss, Jr.  1997.  Anurans as 
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Conant, R., and J. T. Collins.  1991.  A Field Guide to Reptiles and Amphibians: 
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Cowardin, L. M., D. S. Gilmer, and L. M. Mechlin.  1981.  Characteristics of 
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Dahl, T. E.  1990.  Wetlands losses in the United States 1780's to 1980's.  
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Gill, D. E.  1978.  The metapopulation ecology of the red-spotted newt, 
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Hayes, M. P., and M. R. Jennings.  1986.  Decline of ranid frog species in 
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Heyer, W. R., M. A. Donnelly, R. W. McDiarmid, L. C. Hayek, and M. S. Foster, 
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Hoberg, T., and C. Gause.  1992.  Reptiles & amphibians of North Dakota.  North 
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Johnson, D. H.  1996.  Management of northern prairies and wetlands for the 
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Johnson, D. H., and D. L. Larson.  1994.  Amphibian declines: real or perceived?  
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Pechmann, J. H. K., D. E. Scott, R. D. Semlitsch, J. P. Caldwell, L. J. Vitt, 
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Pechmann, J. H. K., and H. M. Wilbur.  1994.  Putting declining amphibian 
     populations in perspective: natural fluctuations and human impacts.  
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Phillips, K.  1990.  Where have all the frogs and toads gone? BioScience 
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Robbins, C. S., D. Bystrak, and P. H. Geissler.  1986.  The Breeding Bird 
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Shirose, L. J., C. A. Bishop, D. M. Green, C. J.MacDonald, R. J. Brooks, N. J. 
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Sjögren, P.  1991.  Extinction and isolation gradients in metapopulations: 
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Stebbins, R. C., and N. W. Cohen.  1995.  A Natural History of Amphibians.  
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     Wake, D. B.  1991.  Declining amphibian populations.  Science 253: 860.

Wheeler, G. C., and J. Wheeler.  1966.  The Amphibians and Reptiles of 
     North Dakota.  University of North Dakota Press, Grand Forks.  104pp.

Wyman, R.L.  1990.  What's happening to the amphibians? Conservation 
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Zimmerman, B. L.  1994.  Audio strip transects.  Pages 92-97 in W. R. Heyer, 
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     Measuring and monitoring biological diversity: standard methods for 
     amphibians.  Smithsonian Institution Press, Washington, DC.