* [https://www.marxists.org/subject/africa/nkrumah/neo-colonialism/introduction.htm Neo-Colonialism, the Last Stage of imperialism] ,Kwame Nkrumah, 1965
* [https://www.marxists.org/subject/africa/nkrumah/neo-colonialism/introduction.htm Neo-Colonialism, the Last Stage of imperialism] ,Kwame Nkrumah, 1965