A Chicago-based producer of other encyclopedias (no, not Encyclopædia Britannica) has threatened to sue Wikipedia for copyright infringement, but has yet to provide any specific examples. However, revelations about misinformation in those encyclopedias, including some that made its way into Wikipedia, have prompted Jimmy Wales to call the author an unsuitable source in any event.
The source in question is Jay Robert Nash, a prolific author who primarily produces reference works and anthologies about crime. He is currently cited as a reference in a number of crime-related articles, most of which can be found by following the what links here feature. Although crime is his specialty, Nash has also branched out into other subjects, including with his 1976 book Darkest Hours: A Narrative Encyclopedia of Worldwide Disasters — From Ancient Times to the Present.
This latter work figured in an earlier incident in which Wikipedia's accuracy was called into question. The incident involved a Washington Post article that was criticized for mischaracterizing the actions of Catholic priests after the 1755 Lisbon earthquake (see archived story). Theresa Carpinelli, a Catholic radio host based in Ohio, took umbrage at its claim that "priests roamed the streets, hanging those they believed had incurred God's wrath." As part of a lengthy rebuttal, she investigated and guessed that the reporter had taken this information from Wikipedia.
When the reporter ultimately responded to her challenge, Carpinelli related that he defended his assertion by citing Nash's encyclopedia in support of it. The reporter quoted a passage that read, "Battalions of priests roved through the debris of Lisbon looking for heretics to burn". The Nash text mentioned in connection with this the tale of "an Englishman named Chase" who supposedly feigned unconsciousness to avoid their attention, according to an account published by Blackwood's Magazine in 1860 (oddly, more than a century after the event).
Carpinelli then went on to attempt a reconstruction of the research in order to dissect and debunk the claims. She determined that the account in question was that of Thomas Chase, and it had originally appeared in The Gentleman's Magazine in 1813. However, she said that she found nothing, either in this version or the later publication by Blackwood's Edinburgh Magazine, suggesting that priests targeted heretics for death or that Chase mentioned faking unconsciousness to avoid them. Carpinelli concluded, "To imply that this information came from Chase’s account in the Blackwood's Magazine, as Jay Robert Nash does, is simply false."
[Update: Although Nash referred to Chase in the same sentence, he did not explicitly state that Chase was his source as to the burning of heretics. Carpinelli has since backed off from her statement that Nash implied this, and Catholic Exchange, the site where it appeared, has apologized for it. Since Chase didn't mention priests, the possibility remains that Nash had another source for the passage about priests burning heretics. Carpinelli indicated that she did not check Nash's entire bibliography, but further investigation by The Wikipedia Signpost located a second possible source—which, however, also fails to support Nash's description. See here for details.]
It seems plausible that Nash's inaccuracy may have fooled not only the reporter, but also the contributor who originally added the same information to Wikipedia. This addition happened in October 2003, a time when citing sources was not emphasized as strongly on Wikipedia, so the ultimate source has never been precisely identified. However, Wikipedia editors are often fans of encyclopedia-type reference works in general and have been known to use these as a resource for transferring information into Wikipedia, so it may well have come from Nash. [Update: As noted on the talk page, Carpinelli points to a website as an intermediate source for the Wikipedia article, but the site clearly appears to draw its information from Nash.]
The offending passage was removed from the Wikipedia article in question, 1755 Lisbon earthquake, and with considerable additional work, it became a featured article in April 2005. Carpinelli herself, who started out quite critical of Wikipedia's response, said that the article "is now so well-written and well-balanced that even I am impressed."
Nash has won "Best Reference" citations from the American Library Association for four of his books, including Darkest Hours. However, he has repeatedly said that his books are seeded with misinformation, including incorrect facts and nonexistent people, so as to catch those who "steal" from his work. Librarian Sally G. Waters, writing for the Library Journal, called his work "fascinating yet flawed" and recommended that it be used only for background research, verifying the information based on the sources in Nash’s bibliography. In the Journal of American History, Richard Maxwell Brown also noted the "numerous errors, omissions, inconsistencies, and anomalies" in Nash’s encyclopedias.
More recently, Nash has claimed that Wikipedia has violated his copyright by either copying or plagiarizing the content for many of its crime-related articles. He has stated on several occasions that he is compiling a list of examples in which Wikipedia allegedly infringes on his work. An actual list has not been provided at this point and so far as is known, no Wikipedia content that infringes on Nash's work has yet been identified by him or anyone else.
Jimmy Wales commented that he would be happy to remove any instances of copying if pointed out, but called Nash's books unfit as sources for Wikipedia regardless of any legal issues. "Nash's work should not be relied upon," Wales concluded, on the grounds that the deliberate insertion of errors "makes it unsuitable as a reference anyway."
Nash once filed a lawsuit against CBS for producing an episode of Simon & Simon with a plotline based around his notion that bank robber John Dillinger was not killed by the FBI in 1934. (Nash focused two separate books on his theory, which has won little acceptance from historians.) His claim of copyright infringement was dismissed on summary judgment, a ruling upheld by an appeals court. The court compared Nash's writing to "speculative works representing themselves as fact" and concluded that he could not claim a copyright on his analysis of historical facts, only his expression of them. The court added that Nash should not be surprised at the result, pointing out, "His own books are largely fresh expositions of facts looked up in other people's books."