“…A noticeable progress has been achieved in spite of substantial complexity of mathematical models of such systems. In the relation with this we mention papers of [1,[4][5][6]9,13,14,[17][18][19][25][26][27][28]. The paper [9], see also [13], has been devoted to analysis the pitchfork and Hopf bifurcations based on using bifurcations theory and the central manifold theorem, obtaining an approximate stability boundary and some other topics.…”