On the contraction principle for a differential equation with unbounded operator coefficient
English version (Springer): Ukrainian Mathematical Journal 27 (1975), no. 2, pp 192-194.
Citation Example: Lykova O. B. On the contraction principle for a differential equation with unbounded operator coefficient // Ukr. Mat. Zh. - 1975. - 27, № 2. - pp. 240–243.
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