TY  - RPRT
TI  - Trailhead quotas
AU  - J. W. van Wagtendonk
AU  - P.R. Coho
PY  - 1986
DO  - 10.1093/jof/84.11.22
UR  - https://pubs.usgs.gov/publication/1007533
ID  - 1007533
ER  -