Letter informing the addressee that he is appointed an official opponent for the defence, requesting to prepare the comment in time, and notifying that all the trip expenses are assumed by SBAS Date: 12.05.1966Original document language: russian Authors: Sergei L. Sobolev Organizations: Sib. Branch of the USSR Ac. Sci. Persons: Andrei Petrovich Ershov Addressee: Victor M. Glushkov