“…The nature of green innovation requires firms to face different economic problems with heterogeneous sources and knowledge interactions (Cainelli, De Marchi, & Grandinetti, ; Florida, ; Horbach et al, ; Ketata et al, ; Oltra & Saint Jean, , ; Rennings & Rammer, ). Interregional and interfirm knowledge spillovers have impacts on green innovators (Costantini, Mazzanti, & Montini, ; Grafström, ).…”