by V. G. Demʹiï¸ a︡nov, M. V. Liï¸ a︡pon, Institut slaviï¸ a︡novedeniiï¸ a︡ (Akademiiï¸ a︡ nauk SSSR), Institut russkogo iï¸ a︡zyka (Akademiiï¸ a︡ nauk SSSR)