1. Alternation;Chandra,1978
2. A combinatorial problem which is complete in polynomial space;Even,1976
3. The complexity of checkers on an N × N board—Preliminary report;Fraenkel,1978
4. Computing a perfect strategy for n × n chess requires time exponential in N;Fraenkel,1981
5. On the computational complexity of algorithms;Hartmanis;Trans. Amer. Math. Soc.,1965