@article{MZ_1972__126_171746,
     author = {Howard A. Levine},
     title = {Some {Uniqueness} and {Growth} {Theorems} in the {Cauchy} {Problem} for {P} utt + {M} ut + {Nu} = 0 in {Hilbert} {Space.}},
     journal = {Mathematische Zeitschrift},
     pages = {345--360},
     publisher = {mathdoc},
     volume = {126},
     year = {1972},
     zbl = {0238.35016},
     url = {http://geodesic.mathdoc.fr/item/MZ_1972__126_171746/}
}