%0 Journal Article %A Jerzy Jezierski %T The Nielsen product formula for coincidences %J Fundamenta Mathematicae %D 1990 %P 183-212 %V 134 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/fm-134-3-183-212/ %R 10.4064/fm-134-3-183-212 %G en %F 10_4064_fm_134_3_183_212