Ehresmann Connection in the Geometry of Nonholonomic Systems
Eigenvalues of Killing tensors and separable webs on Riemannian and pseudo-Riemannian manifolds.
Erratum for "Non singular Hamiltonian systems and geodesic flows on surfaces with negative curvature".
A mistake was found in the reasoning leading to a Lagrangian which we considered as equivalent from the formula for the action S(γ) below the classical mechanical problem (3) on "Non singular Hamiltonian systems and geodesic flows on surfaces with negative curvature", page 271.