In response to Stephen's request for strong statements against the
Marxian notions of exploitation, your student might want to take a look
at N. Scott Arnold's MARX'S RADICAL CRITIQUE OF CAPITALIST SOCIETY
(Oxford 1990). Chapters 3,4, and 5 provide an extremely clear and
comprehensive critique of most of the main variants of Marxian theories
of expolitation. Imagine Bohm-Bawerk as an analytic philosopher . . .
Tony Smith