Artikel Jurnal
Fincher, E. B., author
Abelard-Schuman, 1955
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Polsby, Nelson W., author
Charles Scribner`s Sons, 1964
Buku Teks
Corwin, Edward S., author
New York University Press, 1956
Buku Teks
Polsby, Nelson W., author
Oxford University Press, 1983
Buku Teks