Affiliation: | 1. Department of Wave Processes, Institute of Hydromechanics, NAS of Ukraine, Kiev, Ukraine;2. Mathematical Department, Kirovograd State Pedagogical University, Kirovograd, Ukraine;3. Institut de recherche sur les phénomènes hors équilibre, 49, rue F. Joliot-Curie, BP 146, 13384 Marseille cedex 13, France;4. University of Oslo, Department Mathematics, Oslo, Norway |