Utsa Patnaik, Prabhat Patnaik - A theory of Imperialism
Samir Amin - Contemporary Imperialism
Samir Amin - Law of Worldwide value
Paul Baran, Paul Sweezy - Monopoly Capital
http://digamo.free.fr/barans66.pdf
Rosa Luxemburg - The Accumulation of Capital
Vladimir Illich Lenin - Imperilaism, the Highest Stage of Capitalism