We analyze the evolution of the international collaboration network in photovoltaic research. Using data on scientific publications for the period 1980-2015, we apply social network analysis to trace the evolution of the global network of countries and national research networks of...

We compare two leading regional innovation systems (RIS) in East Germany with two RIS in West Germany of about the same size and internal settlement structure. Our analyses show that differences in the performance between the regions cannot easily be related to the structural properties of the...