Non-Holonomic Connections Following \'Elie Cartan
  In this note we revisit E. Cartan's address at the 1928 International Congress of Mathematicians at Bologna, Italy. The distributions considered here will be of the same class as those considered by Cartan, a special type which we call strongly non-holonomic. We set up the groundwork for using Cartan's method of equivalence (a powerful tool for obtaining invariants associated to geometrical objects), to more general non-holonomic distributions. 
Jair Koiller, Paulo R. Rodrigues and Paulo Pitanga
gr-qc