1. University of Minnesota; 2003 Upper Buford Circle St Paul MN 55108 USA
2. Voyageurs National Park; 360 Highway 11 E International Falls MN 56649 USA
3. Isle Royale National Park; 800 East Lakeshore Drive Houghton MI 49931 USA
4. Department of Natural Sciences and Environmental Health; University College of Southeast Norway; Bø i Telemark Norway