The demon Buer appears in the grimoires Book of Incantations, The Discoverie of Witchcraft, The Grand Grimoire, Pseudomonarchia Daemonum, The Lesser Key of Solomon, and Dictionnaire Infernal
From The Lesser Key of Solomon, Crowley/Mathers edition:
Buer
The Tenth Spirit is Buer, a Great President. He appeareth in Sagittary, and that is his shape when the Sun is there. He teaches Philosophy, both Moral and Natural, and the Logic Art, and also the Virtues of all Herbs and Plants. He healeth all distempers in man, and giveth good Familiars. He governeth 50 Legions of Spirits, and his Character of obedience is this, which thou must wear when thou callest him forth unto appearance.
Timeline of related events
1500
1700
1800
1810
In this decade: Book of Incantations written (lists this demon)
1818
Publication of Dictionnaire Infernal (lists this demon)