Off-Shell Effective Lagrangian for NRQCD and Heavy Quarks Effective   Theory
  derivation of the effective lagrangian for non-relativistic quantum chromodynamics and the heavy quarks effective field theory is given. Our calculation provides of a simple and systematic method of calculation of the full off shell effective lagrangian at tree level including all the $1/m$ corrections. 
J. Gamboa, S. Lepe an L. Vergara