Derived operators and holomorphy conditions of Hilbert space mappings
English version (Springer): Ukrainian Mathematical Journal 42 (1990), no. 10, pp 1175-1179.
Citation Example: Bondar A. V., Romanenko V. Yu. Derived operators and holomorphy conditions of Hilbert space mappings // Ukr. Mat. Zh. - 1990. - 42, № 10. - pp. 1322–1327.
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