Endre Boros Khaled M. Elbassioni Vladimir Gurvich Kazuhisa Makino Vladimir Oudalov A Complete Characterization of Nash-Solvability of Bimatrix Games in Terms of the Exclusion of Certain 2×2 Subgames. 99-109 2008 CSR http://dx.doi.org/10.1007/978-3-540-79709-8_13 conf/csr/2008 db/conf/csr/csr2008.html#BorosEGMO08