@book{steiner-ga91-de,
  author = {Steiner, Rudolf},
  title = {Kosmologie und menschliche Evolution. Einführung in die Theosophie – Farbenlehre},
  series = {Rudolf Steiner Gesamtausgabe},
  number = {91},
  edition = {2},
  publisher = {Rudolf Steiner Verlag},
  address = {Basel},
  year = {2023},
  pagetotal = {506},
  isbn = {978-3-7274-0910-3},
  language = {german},
}

@book{steiner-ga91-en-sol2024,
  author = {Steiner, Rudolf},
  title = {Inner and Outer Evolution},
  publisher = {Steiner Online Library},
  year = {2024},
  language = {english},
  note = {GA 91; edition code SOL2024},
}

@online{anthroposophyai-ga91,
  author = {Steiner, Rudolf},
  title = {Kosmologie und menschliche Evolution. Einführung in die Theosophie – Farbenlehre (GA 91), as served by anthroposophy.ai},
  url = {https://anthroposophy.ai/contents/91/},
  urldate = {2026-10-21},
  organization = {anthroposophy.ai},
  note = {Rudolf Steiner, Kosmologie und menschliche Evolution. Einführung in die Theosophie – Farbenlehre (GA 91), as served by anthroposophy.ai, https://anthroposophy.ai/ga/91/, register entry https://anthroposophy.ai/contents/91/, status as of 2026-10-21: German served; English editions SOL2024.},
}