TY  - RPRT
TI  - An improved "spinning top" for exposure timer checking coupled with a light beam checking device.
AU  - J W Addy
AU  - P Harrison
PY  - 1969
DO  - 10.1259/0007-1285-42-495-229
UR  - https://pubmed.ncbi.nlm.nih.gov/5765701/
ID  - 5765701
ER  -