%0 Journal Article %A Ewa Tyszkowska %T Theory of coverings in the study of Riemann surfaces %J Colloquium Mathematicum %D 2012 %P 173-184 %V 127 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm127-2-3/ %R 10.4064/cm127-2-3 %G en %F 10_4064_cm127_2_3