^Benjamin W. Fortson IV, Indo-European Language and Culture (2004), Malden, MA: Blackwell Publishing, p. 54.
^Frederick Kortlandt, "Glottalic consonants in Sindhi and Proto-Indo-European" (页面存档备份,存于互联网档案馆). Counterarguments exist for his argument of no discernible substrate influence on the development of the specific Sindhi glottalization. See also Michael Witzel, "Substrate Languages in Old Indo-Aryan", Electronic Journal of Vedic Studies 1999 (存档副本(PDF). [2013-09-19]. (原始内容(PDF)存档于2013-09-21).).
^Charles M. Barrack, The Glottalic Theory revisited: a negative appraisal, Indogermanische Forschungen, 2002, pags. 76-95. and Charles M. Barrack, The Glottalic Theory revisited: a negative appraisal.Part II:The typological fallacy underlying the Glottalic Theory, Indogermanische Forschungen, 2003, pags. 1-16.
参考
Charles M. Barrack, The Glottalic Theory revisited: a negative appraisal, Indogermanische Forschungen, 2002, pags. 76-95.
Charles M. Barrack, The Glottalic Theory revisited: a negative appraisal.Part II:The typological fallacy underlying the Glottalic Theory, Indogermanische Forschungen, 2003, pags. 1-16.
Robert S. P. Beekes, Comparative Indo-European Linguistics. John Benjamins, 1995.
Allan R. Bomhard, Reconstructing Proto-Nostratic: Comparative Morphology, Phonology, and Vocabulary. Charleston: Signum, 2007.
James Clackson, Indo-European Linguistics: An Introduction (Cambridge Textbooks in Linguistics). Cambridge: Cambridge University Press, 2007, pp. 40–49.
Anthony Fox, Linguistic Reconstruction. Oxford University Press, 1995.
Thomas V. Gamkrelidze and Vjacheslav V. Ivanov, Indo-European and the Indo-Europeans, translated by Johanna Nichols, 2 volumes. Berlin and New York: Mouton de Gruyter, 1995.
Paul J. Hopper, Glottalized and murmured occlusives in Indo-European.Glossa7:2:1973, 141-166.
Theo Vennemann, Grimm’s Law and loanwords. Transactions of the Philological Society104:2:2006, 129-166.