Caption: This network graph shows all the collaborative relations between countries. Those shown on this graph have published at least 7 joint Medline scientific articles with another country. Each country is represented by a circle, the diameter and size of which are proportional to the number of publications during the period. Coloured clusters represent countries who publish more frequently together. A shorter distance between countries and a thicker line connecting the circles indicate greater collaboration between countries.

Source: publication sources from Pubmed. Analysis tool with Vos Viewer software