TY  - RPRT
TI  - Preserving Native American petroglyphs on porous sandstone
AU  - D.A. Grisafe
PY  - 2017
DO  - 10.1080/2052546.1996.11931813
UR  - https://pubs.usgs.gov/publication/70018632
ID  - 70018632
ER  -