1. Brugmann, K. A.Comparative Grammar of the Indo-Germanic Languages. A Concise Exposition of the History of Sanskrit, Old Iranian (Avestic and Old Persian), Old Armenian, Greek, Latin, Umbro-Samnitic, Old Irish, Gothic, Old High German, Lithuanian and Old Church Slavonic. Volume II. Morphology (Stem-formation and inflexion). Part I. Translated from the German by Seymour Conway, R., and Rouse, W.H.D. (eds). New York: B. Westermann & Co., 1891. p. 241.