TY  - RPRT
TI  - Radioactivity calibrations with the "4π" Gamma ionization chamber and other radioactivity calibration capabilities 
AU  - Calhoun, Jacqueline M
PY  - 1987
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS SP 250-10
DO  - 10.6028/NBS.SP.250-10
ER  -