Bodnar, Istvan (2010年). “Aristotle's Natural Philosophy”. Stanford Encyclopedia of Philosophy. 2022 April 27閲覧。 エラー: 閲覧日が正しく記入されていません。(説明) “In Metaphysics 12.8, Aristotle opts for both the uniqueness and the plurality of the unmoved celestial movers. Each celestial sphere possesses the unmoved mover of its own—presumably as the object of its striving, see Metaphysics 12.6—whereas the mover of the outermost celestial sphere, which carries with its diurnal rotation the fixed stars, being the first of the series of unmoved movers also guarantees the unity and uniqueness of the universe.”