Gough, K. John
Addison-Wesley, 1988
Buku Teks
edited by Adam Ledgeway and Ian Roberts
Cambridge University Press, 2017
Buku Teks
koster, Jan
Foris Publications Dordrecht, 1978
Buku Teks
Dal, Ingerid
Tubingen Max Niemeyer 1952
Buku Teks
McKaughan, Howard P., author
Institute of National Language, 1958
Buku Teks