1. K. Endl, Abstracts of short communications and scientific program, Int. Congress of Mathematicians, 1958, p. 46
2. Untersuchungen über Momentprobleme bei Verfahren vom Hausdorffschen Typus;Endl;Math. Anal.,1960
3. An inequality for Hausdorff means;Hardy;J. London Math. Soc.,1943
4. Divergent Series;Hardy,1949
5. Functional Analysis and Semigroups;Hille,1947