Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a Project Euclid web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact customer_support@projecteuclid.org with any questions.
View Project Euclid Privacy Policy
B. Helffer, J. F. Nourrigat "Approximation d'un système de champs de vecteurs et applications à l'hypoellipticité," Arkiv för Matematik, Ark. Mat. 17(1-2), 237-254, (1979)
