Über die Potenzen $A^\alpha$ $(0\le\alpha\le1)$ eines abgeschlossenen Operators $A$ in einem Banachraum. (German) [On powers $A^\alpha$ $(0\le\alpha\le1)$ of a bounded operator $A$ in a Banach space]. In: General Topology and its Relations to Modern Analysis and Algebra. Proceedings of the second Prague topological symposium, 1966. Academia Publishing House of the Czechoslovak Academy of Sciences, Praha, 1967. pp. 271-273