%0 Journal Article %A O. Richter %A C. Klein %T Algebro-geometric approach to the Ernst equation I. Mathematical Preliminaries %J Banach Center Publications %D 1997 %P 195-204 %V 41 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/-41-1-195-204/ %R 10.4064/-41-1-195-204 %G en %F 10_4064__41_1_195_204