Damian GiaourisSomnath MaitySoumitro BanerjeeVolker PickertBashar ZahawiApplication of Filippov method for the analysis of subharmonic instability in dc-dc converters.899-919200937Int. J. Circuit Theory Appl.8https://doi.org/10.1002/cta.505db/journals/ijcta/ijcta37.html#GiaourisMBPZ09