Mill, Robert Christie
Tourism : the international business
RajaGrafindo Persada, 2000
 Buku Teks
Mill, Robert Christie
Tourism : the international business
Prentice-Hall, 1990
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Wallwork, Adrian
English for Presentations at International Conferences
Springer, 2010
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Cambridge international dictionary of english
editor in chief Paul Procter
Cambridge University Press, 1995
 Buku Referensi
Richards, Jack C.
Interchange English for international communication
Cambridge University Press, 1995
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