@article{CMFD_2011_42_a5,
     author = {U. Boscain and J.-P. Gauthier and F. Rossi},
     title = {Hypoelliptic heat kernel over $3$-step nilpotent {Lie} groups},
     journal = {Contemporary Mathematics. Fundamental Directions},
     pages = {48--61},
     publisher = {mathdoc},
     volume = {42},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/CMFD_2011_42_a5/}
}