TY  - RPRT
TI  - Sonic depth sounder for laboratory and field use
AU  - E.V. Richardson
AU  - Daryl B. Simons
AU  - G.J. Posakony
PY  - 1961
DO  - 10.3133/cir450
UR  - https://pubs.usgs.gov/publication/cir450
ID  - cir450
ER  -