TY  - RPRT
TI  - Determination of a general index of effort in sorting mail by conventional methods 
AU  - Henig, Seymour
PY  - 1960
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS TN 54
DO  - 10.6028/NBS.TN.54
ER  -