6. Conclusions
It is widely acknowledged that the innovation paradigm is shifting towards an imperative for search of external actors to access new ideas for innovation, technologies and resources, or to externally commercialise internal ideas and exploit intellectual property. In this respect, the relationship between the diversity of R&D collaborations and firm's internal innovation efforts, which in turn can positively influence firms' innovation performance, is gaining increasing attention. However, the underlying complexity of the relationship between internal and external knowledge sources, ruled by potential feedback loops and the decomposition of their corresponding influence on innovation performance is largely neglected.