@book{steiner-ga21-de,
  author = {Steiner, Rudolf},
  title = {Von Seelenrätseln (1917)},
  series = {Rudolf Steiner Gesamtausgabe},
  number = {21},
  edition = {5},
  publisher = {Rudolf Steiner Verlag},
  address = {Basel},
  isbn = {978-3-7274-0210-4},
  language = {german},
}

@book{steiner-ga21-en-mp1996,
  author = {Steiner, Rudolf},
  title = {Riddles of the Soul},
  publisher = {Mercury Press},
  year = {1996},
  language = {english},
  note = {GA 21; edition code MP1996},
}

@book{steiner-ga21-en-rsp1970,
  author = {Steiner, Rudolf},
  title = {The Case for Anthroposophy (1970)},
  translator = {Owen Barfield},
  publisher = {Rudolf Steiner Press},
  address = {London, England},
  year = {1970},
  language = {english},
  note = {GA 21; edition code RSP1970},
}

@online{anthroposophyai-ga21,
  author = {Steiner, Rudolf},
  title = {Von Seelenrätseln (1917) (GA 21), as served by anthroposophy.ai},
  url = {https://anthroposophy.ai/contents/21/},
  urldate = {2026-10-21},
  organization = {anthroposophy.ai},
  note = {Rudolf Steiner, Von Seelenrätseln (1917) (GA 21), as served by anthroposophy.ai, https://anthroposophy.ai/ga/21/, register entry https://anthroposophy.ai/contents/21/, status as of 2026-10-20: German served; English editions MP1996, RSP1970.},
}