Fig. 4

Contribution and collaboration among countries and institutions. A The top 20 most productive countries. B The top 20 most cited countries. C contribution and collaboration among countries. D Collaboration map with a minimum number of documents of a country of > 10 publications based on collaboration among countries. E The top 20 most productive institutions. F Collaboration map with a minimum number of documents of a country of > 5 publications based on collaboration among institutions