@book{steiner-ga221-de,
  author = {Steiner, Rudolf},
  title = {Erdenwissen und Himmelserkenntnis},
  series = {Rudolf Steiner Gesamtausgabe},
  number = {221},
  edition = {4},
  publisher = {Rudolf Steiner Verlag},
  address = {Basel},
  year = {2015},
  pagetotal = {194},
  isbn = {978-3-7274-2211-9},
  language = {german},
}

@online{anthroposophyai-ga221,
  author = {Steiner, Rudolf},
  title = {Erdenwissen und Himmelserkenntnis (GA 221), as served by anthroposophy.ai},
  url = {https://anthroposophy.ai/contents/221/},
  urldate = {2026-10-21},
  organization = {anthroposophy.ai},
  note = {Rudolf Steiner, Erdenwissen und Himmelserkenntnis (GA 221), as served by anthroposophy.ai, https://anthroposophy.ai/ga/221/, register entry https://anthroposophy.ai/contents/221/, status as of 2026-10-21: German served; English editions English.},
}