TY  - JOUR
AU  - Robert L. Bryant
TI  - On the Convex Pfaff–Darboux Theorem of Ekeland and Nirenberg
JO  - Symmetry, integrability and geometry: methods and applications
PY  - 2023
VL  - 19
UR  - http://geodesic.mathdoc.fr/item/SIGMA_2023_19_a59/
LA  - en
ID  - SIGMA_2023_19_a59
ER  -