RT Book, Section SR 00 ID doi:10.1007/BFb0002654 A1 Nurminski, E.A. T1 On ɛ-subgradient methods of non-differentiable optimization YR 1979 FD 1979 VO 14 SP 187 OP 195 A2 Bensoussan, A. A2 Lions, J.L. T2 International Symposium on Systems Optimization and Analysis ED 14 PB Springer Berlin Heidelberg PP Germany T3 Lecture Notes in Control and Information Sciences SN 978-3-540-35232-7 AV Published LK https://pure.iiasa.ac.at/id/eprint/14268/ DO 10.1007/BFb0002654