Putt, A. D., & Springer, J. F. (1989). Policy research: Concepts, methods, and applications. Prentice Hall.
Chicago Style aipamenaPutt, Allen D., and J. Frederick Springer. Policy Research: Concepts, Methods, and Applications. Englewood Cliffs, N.J: Prentice Hall, 1989.
MLA aipamenaPutt, Allen D., and J. Frederick Springer. Policy Research: Concepts, Methods, and Applications. Prentice Hall, 1989.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.