Horn, Paul. Dictionary of Persian Etymology (Strassburg, 1893),
Watkins, Calvert. The American Heritage Dictionary of Indo-European Roots, 2nd ed., Houghton Mifflin Co., 2007. *Amazon.com ra,
MacKenzie, David Neil. The dialect of Awroman (Hawraman-i Luhon) Grammatical sketch, texts, and vocabulary. 1966, Kommissionaer: Munksgaard (København).,
Etymonline. Online English Etymology Dictionary. <etymonline.com> by Douglas Harper.,
Julius Pokorny's Indo-European Etymological Dictionary