Comment by Y_Y

Cheney on the MTA is a great paper/algorithm, and I'd like to add (for the benefit of the lucky ten thousand just learning about this) that it's pun on a great old song: Charlie on the MTA ( https://www.youtube.com/watch?v=MbtkL5_f6-4 ). The joke is that in both cases it will never return, either because the subway fare is too high or because you don't want to keep the call stack around.