Bammesberger & Vennemann 2003, σελ. 35: "Greek The fragmentation of the Balkan Proto-Indo-European Sprachbund of phase II around 3000 BC led gradually in the succeeding centuries to the much clearer definition of the languages of the constituent sub-regions." Bammesberger, Alfred· Vennemann, Theo (2003). Languages in Prehistoric Europe. Memmingen: Universitätverlag Winter GmBH Heidelberg. ISBN3825314499.
Georgiev 1981, p. 156: "The Proto-Greek region included Epirus, approximately up to Αυλών in the north including Paravaia, Tymphaia, Athamania, Dolopia, Amphilochia, and Acarnania), west and north Thessaly (Hestiaiotis, Perrhaibia, Tripolis, and Pieria), i.e. more or less the territory of contemporary northwestern Greece)." Georgiev, Vladimir Ivanov (1981). Introduction to the History of the Indo-European Languages. Sofia: Bulgarian Academy of Sciences.
