Order No. 1 of the member of the Provisional Workers’ and Peasants’ Government of Belarus for posts, telegraphs and telephones K.F.Rosenthal on the transformation of the Postal and Telegraphic Department of the Western Region into the People’s Commissariat of Posts, Telegraphs and Telephones
НАРБ. Ф. 809. Оп. 1. Д. 8. Л. 1.