Coba jelasin Uang koin dari Rubel Soviet dong

Daftar mata uang di Eropa

Daftar mata uang yang beredar

Leon Trotsky. The Revolution Betrayed. Chapter 4 - The Struggle for Productivity of Labor, associated with the issuence of the ruble, 1936

A commercial site with some relevant historical information

Catalog of USSR Banknotes from 1922