Das, Veena, author
Oxford University Press, 1982
Buku Teks
Langacker, Ronald W., author
Harcourt, Brace & World, 1968
Buku Teks
Kim, Tae Gon, author
Bogjong, 2008
Buku Teks
Lewis, William Arthur, author
University of Ghana by the Ghana Pub, 1971
Buku Teks
Valin, Robert D. van, author
Cambridge University Press, 2004
eBooks