^ Kloekhorst, Alwin (2008) “ḫar(k)-zi”, in Etymological Dictionary of the Hittite Inherited Lexicon (Leiden Indo-European Etymological Dictionary Series; 5), Leiden, Boston: Brill, →ISBN, pages 355-357
^ De Vaan, Michiel (2008) “arceō”, in Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill, →ISBN, page 51
^ Guus Kroonen (2013) “*fargjan-”, in Alexander Lubotsky, editor, Etymological Dictionary of Proto-Germanic (Leiden Indo-European Etymological Dictionary Series; 11)[1], Leiden, Boston: Brill, →ISBN, pages 128-129
^ Martirosyan, Hrach (2010) “argel”, in Etymological Dictionary of the Armenian Inherited Lexicon (Leiden Indo-European Etymological Dictionary Series; 8), Leiden and Boston: Brill, pages 133-134