TY  - RPRT
TI  - A device for automatic photoelectric control of the analytical gap for emission spectrographs
AU  - John A. Dietrich
AU  - Elmo F. Cooley
AU  - Kenneth J. Curry
PY  - 1977
DO  - 10.3133/cir748
UR  - https://pubs.usgs.gov/publication/cir748
ID  - cir748
ER  -