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@article{MZM_1992_51_5_a20, author = {S. I. Piskarev}, title = {Compactness properties in the theory of the cosine operator functions}, journal = {Matemati\v{c}eskie zametki}, pages = {151--153}, publisher = {mathdoc}, volume = {51}, number = {5}, year = {1992}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1992_51_5_a20/} }
S. I. Piskarev. Compactness properties in the theory of the cosine operator functions. Matematičeskie zametki, Tome 51 (1992) no. 5, pp. 151-153. http://geodesic.mathdoc.fr/item/MZM_1992_51_5_a20/