TY  - RPRT
TI  - "Interchangeable ground-glass joints, stopcocks, and stoppers (fourth edition)" 
PY  - 1939
PB  - National Bureau of Standards
CY  - "Gaithersburg, MD
SN  - NBS CS 21-39
DO  - 10.6028/NBS.CS.21-39
ER  -