Paul, Raymond
WW Norton, 1987
Buku Teks
Cambridge University Press , Cambridge : Cambridge University Press
Majalah, Jurnal, Buletin
Tilburg : Drukkerij Henri Bergmans N.V
Majalah, Jurnal, Buletin
Helen Dwight Reid Educational Foundation, {s.a}
Majalah, Jurnal, Buletin
Nagelkerke, Gerard A.
Leiden Library of the Royal Institute of Linguistics and Anthropology 1982
Buku Referensi