"Gauge transformations for higher-order lagrangians"

Noether's symmetry transformations for higher-order lagrangians are 
studied.  A characterization of these transformations is presented, 
which is useful for finding gauge transformations for higher-order
singular lagrangians.   The case of second-order lagrangians is 
studied in detail.  Some examples that illustrate our results are 
given;  in particular, for the lagrangian of a relativistic particle 
with curvature, lagrangian gauge transformations are obtained, though 
there are not hamiltonian gauge generators for them.