Chain of Dirac spectrum loops of nodes in crossed magnetic and electric fields

This work was supported in part by Project No. 3.2637.2017/4.6 (A.A.P.) of the Ministry of Education and Science of the Russian Federation, by Project No. 15.61.202.2015 of Saint Petersburg State University (E.V.Ch.), and Grant No. IT-756-13 of the Basque Country University (E.V.Ch.).