TY  - RPRT
TI  - Circular of the Bureau of Standards no. 159: United States government master specification for asphalt for mineral-surfaced roofing
PY  - 1924
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS CIRC 159
DO  - 10.6028/NBS.CIRC.159
ER  -