Klaas A. Worp is emeritus professor of papyrology at the Papyrologisch Instituut of the University of Leiden. Among his numerous publications in the field of papyrology The Chronological Systems of Byzantine Egypt, Leiden, 2004, together with Prof. R. S. Bagnall, or Greek Ostraka from Kellis (O.Kellis) (= Dakhleh Oasis Project Monograph 13), Oxford, 2004, should be mentioned. He has been involved with the Roca-Puig papyrological collection project since its very beginning, and has co-authored To the Origins of Greek Stenography. P.Monts.Roca I, Barcelona, 2006, with Sofía Torallas.