Roll, Eric
Prentice-Hall, 1959
Buku Teks
Taylor, Overton H.
Kogakusha Company,Ltd., 1960
Buku Teks
Haney, Lewis H., author
Macmillan, 1949
Buku Teks
Beaud, Michel
Routledge , 1997
Buku Teks
edited by Luca Fiorito, Scott Scheall, Carlos Eduardo Suprinyak
Emerald, 2016
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