%0 Journal Article %A Pigola, S. %A Rimoldi, M. %T Characterizations of Model Manifolds by Means of Certain Differential Systems %J Canadian mathematical bulletin %D 2012 %P 632-645 %V 55 %N 3 %U http://geodesic.mathdoc.fr/articles/10.4153/CMB-2011-134-0/ %R 10.4153/CMB-2011-134-0 %F 10_4153_CMB_2011_134_0