Alexander, John M. (2008). "Capabilities and Social Justice. The Political Philosophy of Amartya Sen and Martha Nussbaum" Ashgate Aldershot/Burlington pp. 198

This is probably the best introduction to the capability approach in social sciences ever written. Emphasis is laid on the philosophical background of the capability approach...Capability theorists will be particularly interested in John Alexander's argument that the capability approach is closer to republicanism than to mainstream liberalism. Throughout the text, the practical relevance of philosophical debates for development issues is made clear. Arguments are carefully devised in a highly readable text.'