@misc{indiciaeb996e0214846,
  title = {The breeding bird survey 1967 and 1968},
  author = {Chandler S. Robbins and Willet T. Van Velzen},
  year = {1969},
  url = {https://pubs.usgs.gov/publication/ssrw124},
  note = {Source identifier: ssrw124}
}