What Is To Be Done? -DOGMATISM AND "FREEDOM OF CRITICISM" https://marxistleninists.org/Lenin/what%20is%20to%20be%20done/dogmatism%20criticism.htm
Mathematical Manuscripts p. 103 http://hiaw.org/defcon6/works/1881/mathematical-manuscripts/p103.html
Lenin Archive English- Hungarian revolution 1919 http://ciml.250x.com/archive/lenin/english/lenin_on_hungarian_revolution_1919_collection_of_quotations.html
Lenin: Instructions for Compiling a Reading Book for Workers and Peasants https://www.marxists.org/archive/lenin/works/1918/dec/x01.htm