Yuefen Chen Liubao Deng Discrete-Time Uncertain LQ Optimal Control with Indefinite Control Weight Costs. 633-639 2016 20 J. Adv. Comput. Intell. Intell. Informatics 4 https://doi.org/10.20965/jaciii.2016.p0633 db/journals/jaciii/jaciii20.html#ChenD16