The Library of Congress is not aware of any extant copies.
Internal evidence consists of all extant copies or editions of the text, together with versions in other languages, citations in other authors, and other sources not belonging to the main textual tradition.
If all extant copies had been mutated, the reversion would have no support.
To give some idea of the importance of the collection, I was shown a narrow volume with two columns of Hebrew on each page that is the oldest and sole extant copy of a printed Haggadah from 1480, Guadalajara, Spain (the library has earlier handwritten Haggadot).
The potential struck him in 1995, when he was assisting Kevin Kiernan, an English professor, on a digital-imaging project involving the only extant copy of "Beowulf," the medieval masterwork, which is in the British Library.
The Life of the Virgin its only extant copy is in a Georgian translation, commonly is, albeit mistakenly, attributed to him, and is considered to be one of the earliest complete biographies of Mary, the mother of Jesus.
God's work — at least as it appeared two weeks ago inside an oak-paneled studio on West 44th Street in Manhattan — consisted of the following acts: A musical archivist removed from its case the sole extant copy of some 1941 session takes of Billie Holiday crooning "All of Me".
In doing research for the earlier episodes, Mr. Burns inadvertently preserved a crucial record when he ended up with the only extant copy of the Port Authority's short film documenting the center's construction.
There is, he reports, no extant copy of the Super Bowl I television broadcast; nobody bothered to keep the tapes.
A court ordered May to give up the work print to the studio, but the only extant copy had mysteriously disappeared.
