Reframing an extract as a quotation constitutes a kind of coauthorship. With no change in wording, the cited passage becomes different. I imagine that the thrill of making an anthology includes the opportunity to become such a coauthor. – Gary Saul Morson, The Words of Others: From Quotations to Culture, 2011
That part of a work of one author found in another is not of itself piracy, or sufficient to support an action; a man may adopt part of the work of another; he may so make use of another’s labors for the promotion of science and the benefit of the public. – Lord Ellenborough, quoted in Bouvier’s Law Dictionary by John Bouvier, 8th