@incollection{JEDP_1981____A9_0,
     author = {Rothschild, Linda P. and Tartakoff, David S.},
     title = {Analyticity for certain solutions of non-hypoelliptic differential operators on the {Heisenberg} group},
     booktitle = {},
     series = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     eid = {9},
     pages = {1--4},
     publisher = {Ecole polytechnique},
     year = {1981},
     zbl = {0478.58039},
     language = {en},
     url = {http://archive.numdam.org/item/JEDP_1981____A9_0/}
}