@article{EJDE_2004__2004__a30,
     author = {Nickel, Gregor},
     title = {A new look at boundary perturbations of generators},
     journal = {Electronic Journal of Differential Equations},
     publisher = {mathdoc},
     volume = {2004},
     year = {2004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2004__2004__a30/}
}