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L'enseignement mathématique: http://www.unige.ch/math/EnsMath/
For longer papers: Ensaios Matemáticos.
Disclaimer/shameless plug: I amwas an editor of the latter.
Disclaimer/shameless plug: I am an editor of the latter.
Disclaimer/shameless plug: I was an editor of the latter.
For longer papers: Ensaios Matemáticos: http://www.sbm.org.br/pageviews.php?menu=5&secao=ensaios,&idcol=129Ensaios Matemáticos.
For longer papers: Ensaios Matemáticos: http://www.sbm.org.br/pageviews.php?menu=5&secao=ensaios,&idcol=129