Robust approach to f(R) gravity
  We consider metric f(R) theories of gravity without mapping them to their
scalar-tensor counterpart, but using the Ricci scalar itself as an "extra"
degree of freedom. This approach avoids then the introduction of a scalar-field
potential that might be ill defined (not single valued). In order to explicitly
show the usefulness of this method, we focus on static and spherically
symmetric spacetimes and deal with the recent controversy about the existence
of extended relativistic objects in certain class of f(R) models.
