@misc{indiciae8c76dbc69d5a,
  title = {Thirty-third winter bird-population study. 5. Upland tulip-tree--maple--oak forest},
  author = {C.S. Robbins},
  year = {1981},
  url = {https://pubs.usgs.gov/publication/5222996},
  note = {Source identifier: 5222996}
}