@misc{indiciae172ea07ad267,
  title = {The Copernicus observations - Interstellar or circumstellar material},
  author = {Steigman, G. and Strittmatter, P. A. and Williams, R. E.},
  year = {1975},
  url = {https://ntrs.nasa.gov/citations/19750052834},
  note = {Source identifier: 19750052834}
}