Gaya APA
Putt, A, D., Springer, J, F. (1989).
Policy research : concepts, methods and applications .
Englewood Cliffs, NJ:
Prentice Hall.
Gaya MLA
Putt, Allen, D.., Springer, J., Fred.
"Policy research : concepts, methods and applications".
Englewood Cliffs, NJ:
Prentice Hall,
1989.
Text.