@article{CRMATH_2006__343_7_463_0,
     author = {Bramanti, Marco and Brandolini, Luca and Lanconelli, Ermanno and Uguzzoni, Francesco},
     title = {Heat kernels for non-divergence operators of {H\"ormander} type},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {463--466},
     publisher = {Elsevier},
     volume = {343},
     number = {7},
     year = {2006},
     doi = {10.1016/j.crma.2006.09.003},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.crma.2006.09.003/}
}