Bolʹshai︠a︡ sovetskai︠a︡ ėnt︠s︡iklopedii︠a︡ /
Schmidt, Otto I︠U︡lʹevich,1891-
Bukharin, Nikolaĭ,1888-1938.
Moskva : Sovetskai︠a︡ ėnt︠s︡iklopedii︠a︡,
1926-47.
Encyclopedias and dictionaries, Russian.