Wróbel, I., Gomilko, A.M. and Zemanek, J. 2007. On a criterion for the uniform boundedness of a <i>C</i><sub>0</sub&gt;-semigroup of operators in a Hilbert space. Ukrains’kyi Matematychnyi Zhurnal. 59, 6 (Jun. 2007), 853-858.