Hartmann, Reinhard R.K.
Routledge, 1998
Buku Referensi
Hartmann, Reinhard R.K.
Routledge , 1998
Buku Referensi
Svensen, Bo
Cambridge University Press, 2009
Buku Teks
edited by Raven I. Mcdavid and Audrey R. Duckert
Foresman and Company,
Buku Teks
edited by Robert F. Ilson
Philadephia John Benjamin Publishing, 1987
Buku Teks