@article{7401,
      recid = {7401},
      author = {Preston, Richard J.},
      title = {North American trees (exclusive of Mexico and tropical  United States) : a handbook designed for field use, with  plates and distribution maps /},
      publisher = {Iowa State University Press,},
      address = {Ames :},
      pages = {xxx, 399 p. :},
      year = {1976},
      note = {Includes index.},
      url = {http://library.usi.edu/record/7401},
}