Letter The author writes how it was not simple "to realize" Andrei A. Markov's forethoughts in the book, but in the whole he is satisfied with the result. Words of a support on the occasion of some initiatives by the addressee. /Handwritten text./ Date: 05.04.1985 Original document language: russian Authors: Nikolai M. Nagorny Persons: Andrei A. Markov Addressee: Andrei Petrovich Ershov