Effective potential for quantum correlation functions.

@article{Cuccoli1991EffectivePF,
  title={Effective potential for quantum correlation functions.},
  author={Cuccoli and Tognetti and Vaia},
  journal={Physical review. A, Atomic, molecular, and optical physics},
  year={1991},
  volume={44 4},
  pages={2734-2737}
}