@misc{indiciae815a8be03613,
  title = {Nonlinear wave equations and constrained harmonic motion.},
  author = {P Deift and F Lund and E Trubowitz},
  year = {1980},
  doi = {10.1073/pnas.77.2.716},
  url = {https://pubmed.ncbi.nlm.nih.gov/16592777/},
  note = {Source identifier: 16592777}
}