TY  - RPRT
TI  - Testing for long-term stability of two-color geodimeters; January 1986 to August 1989
AU  - J. O. Langbein
PY  - 1990
DO  - 10.3133/ofr9091
UR  - https://pubs.usgs.gov/publication/ofr9091
ID  - ofr9091
ER  -