Middel, Anita
Spelling van de werkwoorden
Boekwerk, 1992
 Buku Teks
Outline of linguistic analysis
by Bernard Bloch, George L. Trager
Baltimore, 1942
 Buku Referensi
Atlas of the world's languages
general editors, Christopher Moseley and R.E. Asher; section editors Mary Tait ... [and others]
Routledge, New York Routledge Reference 1994
 Buku Referensi
Atlas of the world's languages
general editors, Christopher Moseley, R.E. Asher
Routledge, 1994
 Buku Referensi
Language, usage and cognition / Joan Bybee
Cambridge University Press, 2010
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