Water level management and contaminant exposure in tree swallows nesting on the upper Mississippi River [electronic resource] / by Thomas Custer and Christine Custer.
Imprint
[Reston, Va.] : U.S. Dept. of the Interior, U.S. Geological Survey, [2005]
Mode of access: Internet from the USGS web site. Address as of 5/10/07: http://pubs.usgs.gov/of/2005/1281/ofr051281.pdf ; current access is available via PURL.
