TY - JOUR IS - 3-4 JF - Acta scientiarum mathematicarum Y1 - 1968/// KW - Hilbert David KW - Természettudomány KW - Matematika KW - M?vel?dés SN - 0001-6969 EP - 312 VL - 29 UR - http://www.acta.hu N1 - Bibliogr.: 312. p. SP - 311 AV - public ID - acta14199 A1 - Istr?tescu Vasile Ion TI - A remark on a class of power-bounded operators in Hilbert space ER -