@article{10_4064_sm217_3_2,
     author = {Adam Bobrowski and Wojciech Chojnacki},
     title = {Isolated points of some sets of bounded cosine families, bounded semigroups, and bounded groups on a {Banach} space},
     journal = {Studia Mathematica},
     pages = {219--241},
     year = {2013},
     volume = {217},
     number = {3},
     doi = {10.4064/sm217-3-2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm217-3-2/}
}