@misc{indiciaed6b16670f122,
  title = {Map showing drainage areas, Ludlow Quadrangle, Massachusetts},
  author = {C.J. Londquist},
  year = {1975},
  doi = {10.3133/mf503d},
  url = {https://pubs.usgs.gov/publication/mf503D},
  note = {Source identifier: mf503D}
}