↑ Edelʹman, D. I. (2020), Etimologičeskij slovarʹ iranskix jazykov [Etymological Dictionary of Iranian Languages] (in Russian), volume 6, Moscow: Vostochnaya Literatura, pages 64-5
↑ Steingass, Francis Joseph (1892), “پله”, in A Comprehensive Persian–English dictionary, London: Routledge & K. Paul