TY  - BOOK
ED  - Bell Telephone Laboratories
TI  - Some illustrations of engineering economics from Bell telephone laboratories
U1  - 338.47621385 
PY  - 1926///
CY  - New York
PB  - Bell Telephone Laboratories
KW  - Engineering economics
N1  - Data prepared for discussion at the Bell System Educational Conference, June, 1926
ER  -