@book{steiner-ga90a-de,
  author = {Steiner, Rudolf},
  title = {Selbsterkenntnis und Gotteserkenntnis I},
  series = {Rudolf Steiner Gesamtausgabe},
  number = {90a},
  edition = {1},
  publisher = {Rudolf Steiner Verlag},
  address = {Basel},
  year = {2018},
  pagetotal = {588},
  isbn = {978-3-7274-0900-4},
  language = {german},
}

@book{steiner-ga90a-en-unk1969,
  author = {Steiner, Rudolf},
  title = {On Apocalyptic Writings},
  year = {1969},
  language = {english},
  note = {GA 90a; edition code UNK1969},
}

@online{anthroposophyai-ga90a,
  author = {Steiner, Rudolf},
  title = {Selbsterkenntnis und Gotteserkenntnis I (GA 90a), as served by anthroposophy.ai},
  url = {https://anthroposophy.ai/contents/90a/},
  urldate = {2026-10-20},
  organization = {anthroposophy.ai},
  note = {Rudolf Steiner, Selbsterkenntnis und Gotteserkenntnis I (GA 90a), as served by anthroposophy.ai, https://anthroposophy.ai/ga/90a/, register entry https://anthroposophy.ai/contents/90a/, status as of 2026-10-20: German served; English editions UNK1969.},
}