TY  - RPRT
TI  - An international standard for a mapping method in bird census work recommended by the International Bird Census committee
AU  - S. Svensson
AU  - K. Williamson
AU  - C. Ferry
AU  - A.H. Joensen
AU  - D. Lea
AU  - H. Oelke
AU  - C.S. Robbins
PY  - 1970
UR  - https://pubs.usgs.gov/publication/5223002
ID  - 5223002
ER  -