@article{AM2_1986__31_137143,
     author = {S.-Y. Shaw and C.-S. Lee and W.-L. Chiou},
     title = {Representation formulas for cosine and sine functions of operators {II.}},
     journal = {Aequationes mathematicae},
     pages = {64--75},
     publisher = {mathdoc},
     volume = {31},
     year = {1986},
     zbl = {0647.47048},
     url = {http://geodesic.mathdoc.fr/item/AM2_1986__31_137143/}
}