by Beklaryan, L. A., Kruchenov, M. B.
Published in Differential equations (01.04.2008)

by Baldygin, V. A., Baldygina, O. A., Grigor’ev, I. N., Kruchenov, M. B., Mysin, I. A., Nikiforov, M. G.
Published in Russian electrical engineering (01.09.2011)