All-Union Population Census of 1926. Volume XXXI. Transcaucasian Socialist Federal Republic of People. Employment. In Russian (ask us if in doubt)./Vsesoyuznaya perepis' naseleniya 1926 goda. Tom XXXI. Zakavkazskaya Sotsialisticheskaya Federativnaya Respublika Narodnost'. Zanyatost'. Central Statistical Office of the USSR. Census Department. Moscow Publishing House of the USSR. 1930. X. 458c. SKUalb4bc716609c3fbbed.