Gaya APA
Webster, C, E. (1986).
THE EXECUTIVE'S GUIDE TO BUSINESS AND ECONOMIC PORECASTING (EDISI 1 CET 1).
usa:
COMPANY CHICAGO.
Gaya MLA
Webster, Charles, E..
"THE EXECUTIVE'S GUIDE TO BUSINESS AND ECONOMIC PORECASTING".
EDISI 1 CET 1
usa:
COMPANY CHICAGO,
1986.
Text.