Papageorgiou, Nikolaos S., Calogero Vetro, and Francesca Vetro. 2019. “Nonlinear Vector Duffing Inclusions With No Growth Restriction on the Orientor Field”. Topological Methods in Nonlinear Analysis 54 (1):257-74. https://apcz.umk.pl/TMNA/article/view/TMNA.2019.041.