Julia, Didier, author
Paris, Librairie Larousse
Buku Referensi
Vachek, Josef
Utrecht Spectrum Editeurs 1960
Buku Referensi
Romeo, Luigi, author
Amsterdam John Benjamins 1979
Buku Referensi
Sykes, Egerton, author
London, J.M. Dent and Sons
Buku Referensi
Metzke, E., author
Heidelberg Kerle 1949
Buku Referensi