1. [m]odern economic causal chains are so complex that only those who are economically isolated and self-sufficient could know” that they are “not part of any system of activities causing unjustifiable deaths;O'Neill;Philosophy and Public Affairs,1975
2. Parfit 's Reasons and Persons
3. Utilitarianism
4. “associative obligations” in his Law's Empire [Cambridge: Harvard University Press, 1986], pp. 195–216.)