The Ball-Box Theorem for a Class of Non-differentiable Tangent   Subbundles
  We show that an analogue of the Ball-Box Theorem for step 2, completely non-integrable bundles from smooth sub-Riemannian geometry hold true for a class of non-differentiable tangent subbundles that satisfy a geometric condition. In the final section of the paper we give examples of such bundles and an application to dynamical systems. 
Sina T\"ureli
math.DG