Gaya APA
A., B.
(1956).
Fundamentals of Economic Geography
(
4th.ed.)
.
Englewood Cliffs:
Prentice-hall Inc.
Gaya MLA
A., BENGSTON,Nels.
"Fundamentals of Economic Geography".
4th.ed.
Englewood Cliffs:
Prentice-hall Inc,
1956.
Teks.