TY  - RPRT
TI  - Geophysical investigations in deep horizontal holes drilled ahead of tunnelling
AU  - R. D. Carroll
AU  - M.J. Cunningham
PY  - 1980
DO  - 10.1016/0148-9062(80)90261-2
UR  - https://pubs.usgs.gov/publication/70012277
ID  - 70012277
ER  -