Citation: Pa. Fuhrmann et U. Helmke, On the parametrization of conditioned invariant subspaces and observer theory, LIN ALG APP, 332, 2001, pp. 265-353
Citation: Pa. Fuhrmann et A. Gombani, On the Lyapunov equation, coinvariant subspaces and some problems related to spectral factorizations, INT J CONTR, 73(12), 2000, pp. 1129-1159