1) Listen to this morning's class, "The Trolley Problem," here. Follow along with the sources here.
2) See the source of Hazon Ish in its context here.
3) Read the full articles that we cited: a) Phillipa Foot's "The Problem of Abortion and the Doctrine of the Double Effect", b) J.J. Thomson's "The Trolley Problem."
4) Further reading: R. J. David Bleich's "Sacrificing the Few to Save the Many."