Languages of Central Sulawesi : checklist, preliminary classification, language maps, wordlists / by Donald F. Barr, Sharon G. Barr in cooperation with C. Salombe

Language change : progress or decay?

Classification and index of the world's languages / C.F. and F.M. Voegelin

Extensive reading activing for teaching language

Linguistic theory, linguistic description and language teaching / Eddy Roulet; Translation by Christopher N. Candlin