Silvère Bonnabel Jean-Jacques E. Slotine A Contraction Theory-Based Analysis of the Stability of the Deterministic Extended Kalman Filter. 565-569 2015 60 IEEE Trans. Autom. Control. 2 https://doi.org/10.1109/TAC.2014.2336991 db/journals/tac/tac60.html#BonnabelS15