^ Wodtko, Dagmar S., Irslinger, Britta, Schneider, Carolin (2008) “*bʰeu̯dʰ-”, in Nomina im indogermanischen Lexikon [Nouns in the Indo-European Lexicon] (in German), Heidelberg: Universitätsverlag Winter, pages 36-37
^ Ringe, Donald (2006) From Proto-Indo-European to Proto-Germanic (A Linguistic History of English; 1)[1], Oxford: Oxford University Press, →ISBN
↑ 5.05.1Beekes, Robert S. P. (2010) “πυνθάνομαι”, in Etymological Dictionary of Greek (Leiden Indo-European Etymological Dictionary Series; 10), volume II, with the assistance of Lucien van Beek, Leiden, Boston: Brill, →ISBN, page 1258
^ Cheung, Johnny (2007) “*baud¹”, in Etymological Dictionary of the Iranian Verb (Leiden Indo-European Etymological Dictionary Series; 2), Leiden, Boston: Brill, →ISBN, pages 14-15
^ Derksen, Rick (2008) “*bľustì”, in Etymological Dictionary of the Slavic Inherited Lexicon (Leiden Indo-European Etymological Dictionary Series; 4), Leiden, Boston: Brill, →ISBN, →ISSN, page 46
^ Adams, Douglas Q. (2013) “paut-”, in A Dictionary of Tocharian B: Revised and Greatly Enlarged (Leiden Studies in Indo-European; 10), Amsterdam, New York: Rodopi, →ISBN, page 437