http://www.atractor.pt/mat/atractores/index-_en.html
http://www.atractor.pt/mat/BilharesConicos/index-_en.html
http://www.atractor.pt/mat/inversao/index-_en.html
http://www.atractor.pt/mat/puzzle-15/index-_en.html
http://www.atractor.pt/mat/Steiner/index-_en.html
http://www.atractor.pt/mat/tangram/index-_en.html

These translations of the original Portuguese version are part of a project involving a team of 27 members of the Center of Mathematics of the University of Coimbra, whose goal is the full translation of the mathematical contents of Atractor's website.