@misc{indiciae23371ae27a38,
  title = {Duck stamps sold within States and counties during sales years 1971-72 through 1980-81},
  author = {Samuel M. Carney and Michael F. Sorensen and Elwood M. Martin},
  year = {1983},
  url = {https://pubs.usgs.gov/publication/ssrw251},
  note = {Source identifier: ssrw251}
}