Clark, Kenneth B.: "Implicahons of Adlerian Theory for an Understanding of Civil Rights Problems and Action", in J. of Indiv. Psych., Vol. XXIII, 2, 1967.
6.
Marx, Karl: Selected Writings in Sociology and Social Philosophy. Ed. T. B. Bottomore and Maximilian Rubel.London: C. A. Watts, 1956. Part III, 4.