TY  - RPRT
TI  - Helium and radon soil-gas surveys of collapse features on the Hualapai Indian Reservation
AU  - J.M. Been
AU  - S.L. Szarzi
PY  - 1989
DO  - 10.3133/ofr89486
UR  - https://pubs.usgs.gov/publication/ofr89486
ID  - ofr89486
ER  -