TY  - RPRT
TI  - An accurate, adjustable double shutter.
AU  - M H Siegel
AU  - E Howard
PY  - 1967
DO  - 10.2466/pms.1967.24.2.673
UR  - https://pubmed.ncbi.nlm.nih.gov/6040247/
ID  - 6040247
ER  -