@article{SF_1991__42_3_135072,
     author = {S. Oharu},
     title = {Nonlinear perturbations of analytical semigroups.},
     journal = {Semigroup forum},
     pages = {127--146},
     publisher = {mathdoc},
     volume = {42},
     number = {3},
     year = {1991},
     zbl = {0721.47052},
     url = {http://geodesic.mathdoc.fr/item/SF_1991__42_3_135072/}
}