Aranya Chakrabortty Ernst Scholtz Time-Scale Separation Designs for Performance Recovery of Power Systems With Unknown Parameters and Faults. 382-390 2011 19 IEEE Trans. Contr. Sys. Techn. 2 http://dx.doi.org/10.1109/TCST.2010.2043105 db/journals/tcst/tcst19.html#ChakraborttyS11