@article{10_4064_sm_44_1_93_105,
     author = {J. Kisy\'nski},
     title = {On cosine operator functions and one-parameter groups of operators},
     journal = {Studia Mathematica},
     pages = {93--105},
     publisher = {mathdoc},
     volume = {44},
     number = {1},
     year = {1972},
     doi = {10.4064/sm-44-1-93-105},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-44-1-93-105/}
}