%0 Journal Article %A S. Topa %T Determination of differential concomitants of the first class of a pair of contravariant vectors in a two-dimensional space %J Annales Polonici Mathematici %D 1967 %P 343-345 %V 19 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/ap-19-3-343-345/ %R 10.4064/ap-19-3-343-345 %G en %F 10_4064_ap_19_3_343_345