@misc{indiciaedb0583db4104,
  title = {The factor-ordering problem must be regulated.},
  author = {NC Tsamis and RP Woodard},
  year = {1987},
  doi = {10.1103/physrevd.36.3641},
  url = {https://pubmed.ncbi.nlm.nih.gov/9958148/},
  note = {Source identifier: 9958148}
}