edited by Ian R. Swingland and Paul J. Greenwood
Clarendon Press, 1983
Buku Teks
Louw, Gideon N.
Longman Scientific and Technical, 1993
Buku Teks
edited by Peter Slater and R. McNeill Alexander
Grolier International, 1986
Buku Referensi
Mufwene, Salikoko S
Cambridge University Press , 2001
Buku Teks
Jiggins, Chris D.
Oxford University Press, 2017
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