@article{TRSPY_1994_203_a36,
     author = {J. Voigt},
     title = {Stability of the essential type of strongly continuous semigroups},
     journal = {Informatics and Automation},
     pages = {469--477},
     publisher = {mathdoc},
     volume = {203},
     year = {1994},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_1994_203_a36/}
}