Calmeyer, Peter (december 1993). ”Crown i. In the Median and Achaemenid periods” (på engelska). Encyclopaedia Iranica. https://www.iranicaonline.org/articles/crown-i. Läst 6 augusti 2023. ”From the reports of the ancient Greeks it appears that the tiara was a soft headdress. They identified one variant with their eastern neighbors and labeled it the “Phrygian cap,” though it was actually worn by nearly all Iranian tribes”
