The Digital Research Library within the University Library System at the University of Pittsburgh has digitized Audubon’s Birds of America. The complete double elephant folio, along with his Ornithological Biography, has been included. Browsing by plate name or by thumbnails is shown, and a search box is provided.
The World Guide to Covered Bridges is a database produced by the National Center for Wood Transportation Structures at the Iowa State University Institute for Transportation. The database allows searching by bridge name, state, county, and the year the covered bridge was built. The results include if the bridge is private or if public access is allowed. A satellite view shows the location of the bridge on a map. Whether it is on the National Historic Landmarks list is also displayed, along with other field definitions.