%0 Journal Article %A Xiao-Guang Qi %A Lian-Zhong Yang %T Differential analogues of the Brück conjecture %J Annales Polonici Mathematici %D 2011 %P 31-38 %V 101 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/ap101-1-3/ %R 10.4064/ap101-1-3 %G en %F 10_4064_ap101_1_3