1. Vector valued Laplace transforms and Cauchy problems;Arendt;Israel J. Math.,1987
2. Interpolationsmethoden zur Behandlung von Approximationsprozessen auf Banachräumen;Berens,1968
3. Direct and inverse mean ergodic theorems with rates for semigroups of operators;Butzer,1981
4. The mean ergodic theorem for cosine operator functions with optimal and non-optimal rates;Butzer;Acta Math. Sci. Hungar.,1995
5. P. L. Butzer, A. Gessinger, Connections between the approximation of semi-group and cosine functions, Atti Sem. Mat. Fis. Univ. Modena