Eliezer has explicitly mentioned Hayakawa in Intensions and Extensions. Axelrod is important to understanding the iterated Prisoner's Dilemma. Singer is one of the better-known proponents of a "shut up and multiply" approach to utilitarianism, agreeing with Eliezer's conclusions in various places (eg). Rawls' notions of the "veil of ignorance" and "reflective equilibrium" have been mentioned in connection with Coherent Extrapolated Volition - when I first came across CEV the similarities with Rawls stuck out like a sore thumb.