TY  - RPRT
TI  - Causes of variation in chemical analyses and physical tests of Portland cement 
AU  - Bean, B L
AU  - Dise, John R
PY  - 1969
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS BSS 17
DO  - 10.6028/NBS.BSS.17
ER  -