^ Wodtko, Dagmar S., Irslinger, Britta, Schneider, Carolin (2008) “*nei̯gu̯-”, in Nomina im indogermanischen Lexikon [Nouns in the Indo-European Lexicon] (in German), Heidelberg: Universitätsverlag Winter, pages 519-520
↑ 5.05.1Beekes, Robert S. P. (2010) “νίζω, -ομαι”, 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, pages 1020-1021
^ Cheung, Johnny (2007) “*naiǰ-”, in Etymological Dictionary of the Iranian Verb (Leiden Indo-European Etymological Dictionary Series; 2), Leiden, Boston: Brill, →ISBN, pages 279-280