Daniel Abondolo (1987). “Hungarian”. In Bernard Comrie. The World's Major Languages. Croom Helm. pp. 577-592. ISBN0709934238
Maria Koptjevskaja-Tamm; Bernhald Wälchli (2001). “The Circum-Baltic Languages”. In Östen Dahl, Maria Koptjevskaja-Tamm. The Circum-Baltic Languages: Typology and Contact. 2. John Benjamins. pp. 615-750. ISBN9027230595
Calvert Watkins (2004). “Hittite”. In Roger D. Woodard. The Cambridge Encyclopedia of the World's Ancient Languages. Cambridge University Press. pp. 551-575. ISBN9780521562560