Tatiana Nikolova-Houston, a doctoral student in the School of Information at the University of Texas at Austin, works with medieval Slavic manuscripts and has created a couple of excellent websites. One is Slavic Medieval Treasures from Bulgaria:
This web site provides textual materials and graphic images dedicated to the development of the production of Slavic medieval manuscripts. The images on this site belong to the manuscript collection of the Historical and Archival Church Institute (HACI) in Sofia, Bulgaria; most of them from the 15th to 17th centuries.
Here, you will find information about: Development of book production in medieval Bulgaria; Major decorative elements of medieval manuscripts; Major decorative styles of manuscripts; Gospel books and their decoration; Other manuscript decoration.
More recently, she has created Byzantine Medieval Hypertexts:
Yes, the idea of hypertexts from the Middle Ages sounds absurd. We think of the Middle Ages as a time of rampant illiteracy and premature death. We remember stories of monks meticulously scribing away in Latin to preserve the heritage of Western civilization against the onslaught of the barbarian hoards, but we tend to forget that the Renaissance was conceived and transmitted to the West through Byzantine monks meticulously scribing away in Greek and Slavic scripts under far greater pressure from the Eastern invasion.
The information on this website presents the theory of hypertext and its medieval application in Byzantine manuscripts, using examples from the Theodore Psalter, a manuscript created in 1066 in the Stoudious monastery near Constantinople. Hypertextuality in this case manifests as a complex interaction between the text and the illustrations in the manuscript and the text as it relates to other manuscripts and its historical context.