Adams, Douglas Q. (1997). Encyclopedia of Indo-European Culture. Taylor & Francis. p. 523. «(..) In their Ukrainian and Polish homeland the Slavs were intermixed and at times overlain by Germanic speakers (the Goths) and by Iranian speakers (Scythians, Sarmatians, Alans) in a shifting array of tribal and national configurations.»
Häkkinen, Jaakko (2012). «Early contacts between Uralic and Yukaghir». En Tiina Hyytiäinen; Lotta Jalava; Janne Saarikivi, eds. Per Urales ad Orientem (Festschrift for Juha Janhunen on the occasion of his 60th birthday on 12 February 2012). Helsinki: Finno-Ugric Society. ISBN978-952-5667-34-9. Consultado el 12 de noviembre de 2013.