Osamu Watanabe Shouwen Tang On Polynomial-Time Turing and Many-One Completeness in PSPACE. 199-215 1992 97 Theor. Comput. Sci. 2 db/journals/tcs/tcs97.html#WatanbeT92 http://dx.doi.org/10.1016/0304-3975(92)90074-P