TY  - RPRT
TI  - Report on the evaluation of twenty-one coating-grade roofing asphalts 
AU  - Greenfeld, Sidney H
PY  - 1956
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS RPT 4732
DO  - 10.6028/NBS.RPT.4732
ER  -