TY  - RPRT
TI  - A statistical chain ratio method for determining the distribution of mail by destination 
AU  - Severo, Norman C
PY  - 1957
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS RPT 5685
DO  - 10.6028/NBS.RPT.5685
ER  -