Marx and Engels. First Indian War of Independence 1857-58 http://hiaw.org/defcon6/works/1857/07/15.html
The German Ideology: Chapter 1 - On Feuerbach https://marxistleninists.org/M&E/1845/german-ideology/ch01.htm
Lenin: Letter to the International Socialist Bureau https://www.marxists.org/archive/lenin/works/1905/sep/16.htm
The German Ideology by Karl Marx and Frederick Engels https://marxistleninists.org/M&E/1845/german-ideology/ch03j.htm