@book{steiner-ga166-de,
  author = {Steiner, Rudolf},
  title = {Notwendigkeit und Freiheit im Weltengeschehen und im menschlichen Handeln},
  series = {Rudolf Steiner Gesamtausgabe},
  number = {166},
  edition = {4},
  publisher = {Rudolf Steiner Verlag},
  address = {Basel},
  year = {2018},
  pagetotal = {154},
  isbn = {978-3-7274-1661-3},
  language = {german},
}

@book{steiner-ga166-en-ap1988,
  author = {Steiner, Rudolf},
  title = {Necessity and Freedom},
  publisher = {Anthroposophic Press},
  year = {1988},
  language = {english},
  note = {GA 166; edition code AP1988},
}

@online{anthroposophyai-ga166,
  author = {Steiner, Rudolf},
  title = {Notwendigkeit und Freiheit im Weltengeschehen und im menschlichen Handeln (GA 166), as served by anthroposophy.ai},
  url = {https://anthroposophy.ai/contents/166/},
  urldate = {2026-10-21},
  organization = {anthroposophy.ai},
  note = {Rudolf Steiner, Notwendigkeit und Freiheit im Weltengeschehen und im menschlichen Handeln (GA 166), as served by anthroposophy.ai, https://anthroposophy.ai/ga/166/, register entry https://anthroposophy.ai/contents/166/, status as of 2026-10-21: German served; English editions AP1988.},
}