Optimization and Applications 9th International Conference, OPTIMA 2018, Petrovac, Montenegro, October 1-5, 2018, Revised Selected Papers - Evtushenko, Yury; Evtushenko, Yury; Jaćimović, Milojica; Jaćimović, Milojica; Khachay, Michael; Khachay, Michael; Kochetov, Yury; Kochetov, Yury; Malkova, Vlasta; Malkova, Vlasta; Posypkin, Mikhail; Posypkin, Mikhail (Springer International Publishing : Imprint: Springer, 2019)