- Manuscript draft of a two-page letter from Lysander Spooner in Boston [Massachusetts] to Gerrit Smith in Peterboro, New York, dated July 3, 1848, in which Spooner asks for the return of the copyrights to his works so that he might raise funds against it for the publication of his newest book., New-York Historical Society
- Four-page letter from Lysander Spooner in Boston [Massachusetts] to Gerrit Smith in Peterboro, New York, dated July 3, 1848, in which Spooner asks for the return of the copyrights to his works so that he might raise funds against them for the publication of his newest book., New-York Historical Society
- Manuscript draft of a twelve-page letter from Lysander Spooner in Worcester [Massachusetts] to Gerrit Smith, dated April 23, 1850, in which Spooner discusses specific instances of copyright infringement committed by Smith in the publication of "Gerrit Smith's Constitutional Argument.", New-York Historical Society
- Three-page letter dated April 15, 1853, from L. [Lysander] Spooner in Boston [Massachusetts] to [George] Bradburn, notifying him of the death of Ernest Hidlreth, the youngest child of Richard and Caroline Hildreth, as well as discussing Spooner's newest work on the "Law of Intellectual Property" and a controversy between Horace Mann and Wendell Phillips., New-York Historical Society