@article{articlea00c6e92,
title   = {Global solvability and propagation of regularity of sums of squares on compact manifolds},
author = {Araújo, Gabriel and Ferra, Igor Ambo and Ragognette, Luis Fernando},
year = {2022},
doi = {10.1007/s11854-022-0223-6},
journal   = {Journal d'Analyse Mathematique}
}