Fowler, Robert Booth
Praeger, 1985
Buku Teks SO
Sargent, Lyman Tower
Wadsorth Thompson Learning, 2003
Buku Teks
Sargent, Lyman Tower
Brooks Cole, 1990
Buku Teks
Kymlicka, Will
Clarendon Press, 1990
Buku Teks
Macridis, Roy C.
Little, Brown, 1983
Buku Teks