TY  - RPRT
TI  - Trends in Engineering Geologic and Related Mapping 1972–1983
AU  - David J. Varnes
AU  - Jeffrey R. Keaton
PY  - 1983
DO  - 10.2113/gseegeosci.xxi.3.255
UR  - https://pubs.usgs.gov/publication/70011178
ID  - 70011178
ER  -