%0 Journal Article %A Leonid Makar-Limanov %A Andrzej Nowicki %T On the ring of constants for derivations of power series rings in two variables %J Colloquium Mathematicum %D 2001 %P 195-200 %V 87 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm87-2-5/ %R 10.4064/cm87-2-5 %G en %F 10_4064_cm87_2_5