Figure 1. Grouped categories of nations

From

The World at Their Feet: A Combined Historical Ranking of Nations Competing in Football and Futsal

Richard Moore, Dr Girish Ramchandani, Steve Bullough, Simon Goldsmith, Lee Edmondson, Dr Daniel Berdejo-del-Fresno

American Journal of Sports Science and Medicine. 2018, 6(2), 49-59 doi:10.12691/ajssm-6-2-3