@article{IM_1987__88_143447,
     author = {G. Kalai},
     title = {Rigidity and the lower bound {Theorem} l.},
     journal = {Inventiones mathematicae},
     pages = {125--152},
     year = {1987},
     volume = {88},
     zbl = {0624.52004},
     url = {http://geodesic.mathdoc.fr/item/IM_1987__88_143447/}
}