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Buku Referensi
Simpson, Paul, author
Routledge , 2004
Buku Teks
Enkvist, Nils Erik
Mouton, 1973
Buku Teks
Simpson, Paul, author
Routledge , 2004
Buku Teks
Svensen, Bo, author
Cambridge University Press, 2009
Buku Teks