@article{10_4064_sm195_2_4,
     author = {Marta Tyran-Kami\'nska},
     title = {Ergodic theorems and perturbations of
 contraction semigroups},
     journal = {Studia Mathematica},
     pages = {147--155},
     publisher = {mathdoc},
     volume = {195},
     number = {2},
     year = {2009},
     doi = {10.4064/sm195-2-4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm195-2-4/}
}