@article{GDZPPN002550458, title = {A representation formula for strongly continuous cosine families.}, journal = {Aequationes mathematicae}, volume = {20}, year = {1980}, pages = {251-256}, zbl = {0467.47037}, url = {http://dml.mathdoc.fr/item/GDZPPN002550458} }
Webb, G.F. A representation formula for strongly continuous cosine families.. Aequationes mathematicae, Tome 20 (1980) pp. 251-256. http://gdmltest.u-ga.fr/item/GDZPPN002550458/