@misc{indiciae2a166d2f8322,
  title = {Spectral rigidity for degenerate integrable systems.},
  author = {D Biswas and M Azam and SV Lawande},
  year = {1991},
  doi = {10.1103/physreva.43.5694},
  url = {https://pubmed.ncbi.nlm.nih.gov/9904885/},
  note = {Source identifier: 9904885}
}