Periodic solutions of second-order wave equations. IV
English version (Springer): Ukrainian Mathematical Journal 40 (1988), no. 6, pp 639-644.
Citation Example: Khoma G. P., Mitropolskiy Yu. A. Periodic solutions of second-order wave equations. IV // Ukr. Mat. Zh. - 1988. - 40, № 6. - pp. 757–763.
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