Clarke, Francis. “Continuity of Solutions to a Basic Problem in the Calculus of Variations”. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE 4, no. 3 (December 4, 2009): 511-530. Accessed May 26, 2026. https://journals-dev.sns.it/index.php/annaliscienze/article/view/77.