SkjaervØ (2011:350), quoted in Elst, Koenraad (2018). Still no trace of an Aryan invasion: A collection on Indo-European origins.
Zoroastrianism (…) originated some four millennia ago.
Attribution
Quote text and notes from Wikiquote: Prods Oktor Skjaervo (page history), available under CC BY-SA 4.0. Source quality and labels are our own summary of what Wikiquote records.