TY  - RPRT
TI  - Techniques and results of nongame bird monitoring in North America
AU  - C.S. Robbins
AU  - D. Bystrak
AU  - P.H. Geissler
PY  - 1980
UR  - https://pubs.usgs.gov/publication/5210239
ID  - 5210239
ER  -