Kloekhorst Alwin. Proto-Indo-European 'thorn'-clusters

Historische Sprachforschung / Historical Linguistics. — 2014. — Volume 127. — pp. 43-67Since the beginning of Indo-European linguistics, the group of words in which the Skt. cluster kṣ corresponds to Gk. KT have received much attention. According to Brugmann, these clusters must reflect a combination of a PIE velar plus “þ-Laute” (hence the name “thorn”-clusters), which was the standard view for many decades