TY  - RPRT
TI  - Penetration of gamma rays from isotropic sources through aluminum and concrete 
AU  - Berger, Martin J
PY  - 1959
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS TN 11
DO  - 10.6028/NBS.TN.11
ER  -