When some variational properties force convexity

Volle, M.; Hiriart-Urruty, J.-B.; Zălinescu, C.

ESAIM: Control, Optimisation and Calculus of Variations, Volume 19 (2013) p. 701-709

Duality for the level sum of quasiconvex functions and applications

Volle, M.

ESAIM: Control, Optimisation and Calculus of Variations, Volume 3 (1998) p. 329-343

On a convolution operation obtained by adding level sets : classical and new results

Seeger, A.; Volle, M.

RAIRO - Operations Research - Recherche Opérationnelle, Volume 29 (1995) p. 131-154