Barr, Donald F.
Languages of Central Sulawesi : checklist, preliminary classification, language maps, wordlists
Percetakan Universitas Cenderawasih, 1979
 Buku Klasik
Aitchison, Jean, 1938-
Language change : progress or decay?
Cambridge University Press, 1995
 Buku Teks SO
Extensive reading activing for teaching language
Julian Bamfor edited by
:Cambridge University Press, 2004
 Buku Teks SO
Voegelin, C.F.
Classification and index of the world's languages / C.F. and F.M. Voegelin
Elsevier, 1977
 Buku Teks
Roulet, Eddy
Linguistic theory, linguistic description and language teaching
Longman, 1979
 Buku Teks SO