Steven J. Heyman, "Positive and negative liberty." Chicago-Kent Law Review. 68 (1992): 81-90. online
marxists.org
George Klosko, History of Political Theory: An Introduction: Volume II: Modern (2nd ed.), Oxford University Press, 2013, p. 465: "we should note that Hegel's realization of the distance between his own and the traditional liberal conception of freedom, which he calls "abstract freedom," is clear in his embrace of positive freedom [in PR §149A]".
