Analogue of Kelli's condition for systems of hyperbolic equations
English version (Springer): Ukrainian Mathematical Journal 33 (1981), no. 1, pp 1-5.
Citation Example: Zubarev S. V. Analogue of Kelli's condition for systems of hyperbolic equations // Ukr. Mat. Zh. - 1981. - 33, № 1. - pp. 3–8.
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