@article{1391742,
      author = {Beard, Robert D.,},
      url = {http://library.usi.edu/record/1391742},
      title = {Rockhounding Delaware, Maryland, and the Washington, DC  metro area : a guide to the areas' best rockhounding sites  /},
      recid = {1391742},
      pages = {1 online resource (283 pages) :},
}