Kulish, V. V., Gubanov, I. V., Dien, L. H., Viet, N. A. and Lysenko, O. V. (2009) “A New Approach to the Theory of Hierarchic Wave-oscillation Dynamic Systems”, Communications in Physics, 19(1), pp. 9–18. doi: 10.15625/0868-3166/19/1/233.