TY  - RPRT
TI  - Small-format cameras and fine-grain film used for waterfowl population studies
AU  - Edgar L. Ferguson
AU  - David S. Gilmer
PY  - 1980
DO  - 10.2307/3808021
UR  - https://pubs.usgs.gov/publication/1001696
ID  - 1001696
ER  -