^Napu at Ethnologue (18th ed., 2015) (subscription required)
^Martens, Michael P. (1989). "The Badaic Languages of Central Sulawesi" (PDF). In Sneddon, James N. (ed.). Studies in Sulawesi Languages, Part 1. Jakarta: Universitas Katolik Indonesia Atma Jaya. pp. 19–53.
Further reading
Hanna, Roger; Hanna, Leanne (1991). "Phonology of Napu" (PDF). In Rene van den Berg (ed.). Workpapers in Indonesian Languages and Cultures (PDF). Vol. 12, Sulawesi Phonologies. Ujung Pandang, Sulawesi: Summer Institute of Linguistics. pp. 150–78. ISBN979-8132-85-8.
Garantjang, Ahmad; Kadjia, Dahlan; B., Nuhung; Sulaeman, Hanafi (1989). Struktur Bahasa Napu [Napu Structure]. Seri Pustaka Penelitian, 172 (in Indonesian). Jakarta: Departemen Pendidikan dan Kebudayaan. ISBN979-459-040-1 – via repositori.kemdikbud.go.id.
Limba, Sinus; Mondolu, Tr.; Nelloh, Karel; Tokari, N. P.; Tebo, Harongi; Gae, Maniba (2011), Kamus Napu–Indonesia–Inggris [Napu–Indonesian–English Dictionary] (in Indonesian), Sulawesi Language Alliance