@misc{indiciae7afbbda433c3,
  title = {Surficial Geologic Map of the Ashby-Lowell-Sterling-Billerica 11-Quadrangle Area in Northeast-Central Massachusetts},
  author = {Byron D. Stone and Janet Radway Stone},
  year = {2007},
  doi = {10.3133/ofr20061260c},
  url = {https://pubs.usgs.gov/publication/ofr20061260C},
  note = {Source identifier: ofr20061260C}
}