The Problem of Hidden Variables in Quantum Mechanics Simon KochenE. Specker Indiana University Mathematics Journal 1968 text pdf 10.1512/iumj.1968.17.17004 10.1512/iumj.1968.17.17004 en Indiana Univ. Math. J. 17 (1968) 59 - 87 state-of-the-art mathematics http://iumj.org/access/