Solvability of a Lie algebra of vector fields implies their   integrability by quadratures
  We present a substantial generalisation of a classical result by Lie on integrability by quadratures. Namely, we prove that all vector fields in a finite-dimensional transitive and solvable Lie algebra of vector fields on a manifold can be integrated by quadratures. 
J.F. Cari\~nena, F. Falceto and J. Grabowski
math-ph math.MP