TY - RPRT TI - The internal structure of sand bars on the Colorado River, Grand Canyon, as determined by ground-penetrating radar AU - Walter A. Barnhardt AU - Robert Kayen AU - David Rubin AU - Diane L. Minasian PY - 2001 DO - 10.3133/ofr01425 UR - https://pubs.usgs.gov/publication/ofr01425 ID - ofr01425 ER -