To cite Spectran in publications use:

Zauner J (2023). “Spectran: Visual and Non-Visual Spectral Analysis with an Emphasis on Education and Presentation-Ready Diagrams.” a publication from LiTG e.V. (Deutsche Lichttechnische Gesellschaft e.V.), https://litgde.github.io/Spectran/.

Corresponding BibTeX entry:

  @Misc{,
    title = {Spectran: Visual and Non-Visual Spectral Analysis with an
      Emphasis on Education and Presentation-Ready Diagrams},
    author = {Johannes Zauner},
    year = {2023},
    note = {a publication from LiTG e.V. (Deutsche Lichttechnische
      Gesellschaft e.V.)},
    url = {https://litgde.github.io/Spectran/},
  }