TY  - RPRT
TI  - GIS for mapping waterfowl density and distribution from aerial surveys
AU  - W.I. Butler
AU  - R.A. Stehn
AU  - G.R. Balogh
PY  - 1995
UR  - https://pubs.usgs.gov/publication/1013312
ID  - 1013312
ER  -