Abhijit G. KallapurIan R. PetersenSreenatha G. AnavattiA Discrete-Time Robust Extended Kalman Filter for Uncertain Systems With Sum Quadratic Constraints.850-854200954IEEE Trans. Autom. Control.4https://doi.org/10.1109/TAC.2008.2010962db/journals/tac/tac54.html#KallapurPA09