Northern Kurdish: Lua error in Module:parameters at line 290: Parameter 1 should be a valid language or etymology language code; the value "ku" is not valid. See WT:LOL and WT:LOL/E.
^ De Vaan, Michiel (2008) “speciō, -ere”, in Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill, →ISBN, pages 578-579
^ Beekes, Robert S. P. (2010) “σκέπτομαι”, 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 1347-1348
^ Cheung, Johnny (2007) “*spas”, in Etymological Dictionary of the Iranian Verb (Leiden Indo-European Etymological Dictionary Series; 2), Leiden, Boston: Brill, →ISBN, pages 353-354