@article{article9b9a7fbe,
title   = {Necessary and sufficient conditions for the local solvability in hyperfuctions of a class of systems of complex vector fields},
author = {Cordaro, Paulo Domingos and Trèves, François},
year = {1995},
doi = {10.1007/bf01241132},
journal   = {Inventiones Mathematicae}
}