@misc{indiciae194df957554a,
  title = {HELIOS Configuration for Close Sun Flyby},
  author = {Lex, J. and Koppe, H. and Keller, E. W.},
  year = {1970},
  url = {https://ntrs.nasa.gov/citations/19980151098},
  note = {Source identifier: 19980151098}
}