@misc{indiciae66bf7af86956,
  title = {Serial and parallel multilevel systems.},
  author = {E Kyrölä and M Lindberg},
  year = {1987},
  doi = {10.1103/physreva.35.4207},
  url = {https://pubmed.ncbi.nlm.nih.gov/9898011/},
  note = {Source identifier: 9898011}
}