@article{239421,
      recid = {239421},
      author = {Ruhl, Henry A.},
      title = {Distribution and abundance of submersed aquatic vegetation  in the tidal Potomac River and upper Potomac Estuary,  Maryland, Virginia, and the District of Columbia, 1993-1998  [microform] /},
      publisher = {Dept. of the Interior, U.S. Geological Survey ;},
      address = {Reston, Va. :},
      pages = {iv, 39 p. :},
      year = {1999},
      note = {Cover title.},
      url = {http://library.usi.edu/record/239421},
}