%0 Journal Article %A K. Urbanik %T On algebraic operations in idempotent algebras %J Colloquium Mathematicum %D 1964 %P 129-157 %V 13 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm-13-2-129-157/ %R 10.4064/cm-13-2-129-157 %G en %F 10_4064_cm_13_2_129_157