This Proto-Batak entry contains reconstructed terms and roots. As such, the term(s) in this entry are not directly attested, but are hypothesized to have existed based on comparative evidence.
K. A. Adelaar. 1981. "Reconstruction of Proto-Batak Phonology". In Robert A. Blust (ed.), Historical Linguistics in Indonesia: Part I, 1-20. Jakarta: Universitas Katolik Indonesia Atma Jaya.