@article{MABA_1991_5_4_a5,
     author = {Michael I. Gil},
     title = {Estimate for {Norm} of {Solutions} of {Nonautonomous} {Equations} in {Hilbert} {Space}},
     journal = {Mathematica balkanica},
     pages = {341},
     publisher = {mathdoc},
     volume = {5},
     number = {4},
     year = {1991},
     url = {http://geodesic.mathdoc.fr/item/MABA_1991_5_4_a5/}
}