Kassick, Enio V. “Deriving The Canonical Equivalent Circuit For Small Signal & Low Frequency Ac Model For The Sepic And Zeta PWM Dc-Dc Converters With Two-Port Network”. Eletrônica De Potência, vol. 16, no. 4, Nov. 2011, pp. 376-82, doi:10.18618/REP.20114.376382.