. . . . "Peter J. DeVries" . . . . "en" . . "Cygnus olor (Gmelin, 1789)" . . . "http://lod.geospecies.org/ses/8GZD4.html" . . "2010-07-15T12:42:09-0500" . "GeoSpecies Knowledge Base Page: Species Cygnus olor (Gmelin, 1789)" .