THE RENOVATED COPTIC MUSEUM is covered in much more detail in an article ("Coptic treasures get the home they deserve") in Al-Ahram. This in particular is of interest:

Perhaps the most prized exhibit, though, is a copy of The Psalms of David, given a gallery to itself. Philip Halim, director general of the Coptic Museum, told the Weekly that the copy is the only complete version of the psalms ever found. It includes 151 psalms written by David, and the psalms of other Old Testament Prophets, including Solomon and Essaf. Written in Coptic, on very fine vellum, the copy dates back to the fifth century and was found in 1987, buried in sand beneath the head of a child mummy in a tomb in the upper Egyptian city of Beni Sueif.

Along with the psalms is an ankh-shaped piece of ivory which was used as a book marker.

Cool. I'm not sure who Essaf is, though.

UPDATE: Oh, of course: Asaph.