@article{AFM_2002_27_1_a17,
     author = {Min Chen},
     title = {Differentiability and rigidity theorems},
     journal = {Annales Fennici Mathematici},
     pages = {221--230},
     publisher = {mathdoc},
     volume = {27},
     number = {1},
     year = {2002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AFM_2002_27_1_a17/}
}