Canonical formulation of standard cosmology: Direct quantum approach.

@article{Novello1996CanonicalFO,
  title={Canonical formulation of standard cosmology: Direct quantum approach.},
  author={Novello and Salim and MC MottadaSilva and Klippert},
  journal={Physical review. D, Particles and fields},
  year={1996},
  volume={54 10},
  pages={6202-6205}
}