A quotation skeleton is a quotation reduced to 8-word search phrases, annotations and short prefixes. The quotation itself awaits copyright clearance from the copyright holder.
Thesa provides the full text of quotations that are in the public domain. Most of these quotations were published before 1928.
About a sixteenth of quotation titles share a phrase of six words or more with the quoted text. This is considered fair use. If an author captures the idea succinctly, the title may use the author's words. In rare cases, a sentence is used. Quine provides an example.
Quote: meaning is what essence becomes when it is divorced from the object of reference and wedded to the word
Later, Thesa will expand its use of fair use to include a small number of quotations from each author. Thesa adds value to these quotations by adding descriptive titles and by linking a quotation to related quotations. Fair use will be dropped if requested by an author or copyright holder.
HaithiTrust (https://www.hathitrust.org) is a reliable source of public domain material.