@article{CMH_1981__56_139866,
     author = {Michael Gromov},
     title = {Curvature, diameter and {Betti} numbers.},
     journal = {Commentarii mathematici Helvetici},
     pages = {179--195},
     publisher = {mathdoc},
     volume = {56},
     year = {1981},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMH_1981__56_139866/}
}