@Article{ bardra, author = { Bardi, Martino and Dragoni, Federica }, title = { Convexity and semiconvexity along vector fields }, journal = { Calc. Var. Partial Differential Equations }, year = { 2011 }, volume = { 42 }, pages = { 405--427 }, URL = { http://cvgmt.sns.it/paper/942/ }, note = { cvgmt preprint} }