@article{NUMA_1992__63_1_133686,
     author = {Irena Lasiecka},
     title = {Convergence rates for the approximations of the solutions to algebraic {Riccati} {Equations} with unbounded coefficients: case of analytic semigroups.},
     journal = {Numerische Mathematik},
     pages = {357--390},
     publisher = {mathdoc},
     volume = {63},
     number = {1},
     year = {1992},
     zbl = {0766.65055},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1992__63_1_133686/}
}