Co-authorship network according to the income-level of the country of origin (anonymized).

<p>Network composed of 1339 authors (or nodes). Authors from high-income countries are in blue, middle-income countries in green and low-income countries in red. Nodes were resized according to the degree of centrality.</p

International collaboration by economic groups of countries (1996–2012)

<p>International collaborations were considered when the paper involved different countries, 98 in total. The combination of countries according to economic groups considered income extremes. For example, if there was a collaboration involving one high-income country and two middle-income countries, this was classified as a high- and middle-income country collaboration, not as middle and middle.</p

Size of collaborations^* in respect to number of authors, institutions and countries

<p>*Each paper with more than one author was considered to be a scientific collaboration.</p

Co-authorship network according to betweenness centrality (anonymized).

<p>Network composed of 1339 authors (or nodes). Nodes were resized according to degree of centrality. The colour of the node was determined by its betweenness centrality. Dark blue nodes represent higher betweenness centrality. Conversely, light blue nodes represent lower betweenness centrality.</p