@article{ASNSP_2012_5_11_2_437_0,
     author = {Frentz, Marie and Garofalo, Nicola and G\"otmark, Elin and Munive, Isidro and Nystr\"om, Kaj},
     title = {Non-divergence form parabolic equations associated with non-commuting vector fields: boundary behavior of nonnegative solutions},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {437--474},
     publisher = {Scuola Normale Superiore, Pisa},
     volume = {Ser. 5, 11},
     number = {2},
     year = {2012},
     mrnumber = {3011998},
     zbl = {1258.31005},
     language = {en},
     url = {http://archive.numdam.org/item/ASNSP_2012_5_11_2_437_0/}
}