@misc{indiciae408f3e411c5f,
  title = {Free heterotic string field theory.},
  author = {W Chen and Y Yu},
  year = {1987},
  doi = {10.1103/physrevd.35.3915},
  url = {https://pubmed.ncbi.nlm.nih.gov/9957654/},
  note = {Source identifier: 9957654}
}