Reference materials used includes but is not limited to:
Birley, B. and Greene, E. 2006 The Roman Jewellery from Vindolanda, beads, intaglios, finger rings, bracelets and ear-rings. Vindolanda Res.Rep new series 4, fasc5.
Brugmann, Birte. Glass Beads from Anglo-Saxon Graves: A Study on the Provenance and Chronology of Glass Beads from Anglo-Saxon Graves, Based on Visual Examination: Oxbow Books, 2004
Callmer, Johann. “Scandinavian Beads, ca. AD 700-1100″, Ornaments from the Past: Bead Studies After Beck. Ian C. Glover, Helen Hughes Brock and Julian Henderson, eds. London: The Bead Study Trust, 2003, 38-46
Carlsson, Dan. Viking Beads from Frojel Port of Trade, Gotland, Sweden: CD-rom, http://www.arkeodok.com/Vikingcd.html
Dubin, Lois S. The History of Beads: 30,000 BC to the Present. NY: H N Abrams, 1987
Guido, Margaret. The Glass Beads of Anglo-Saxon England, c. AD 400-700: A Preliminary Visual Classification of the More Definitive and Diagnostic Types. Rochester, NY: Boydell Press for the Society of Antiquarians of London, 1999
Guido, Margaret. The Glass Beads of the Prehistoric and Roman Periods in Britain and Ireland. London: Society of Antiquaries of London: Distributed by Thames and Hudson, 1978
Sode, Torbe. “Viking Age glass beads from Ribe, Denmark, in the light of ethnographic research”, Ornaments from the Past: Bead Studies After Beck.
Ian C. Glover, Helen Hughes Brock and Julian Henderson, eds. London: The Bead Study Trust, 2003, 47-58
Sode, Torben. “The glass bead material from Ribe, Denmark”, in Viking Heritage magazine, 3/2003, 17-20 and accompanying articles by the author in the same issue.
Online research from The York Archaeological Trust, The Portable Antiquities Scheme database, various online image galleries of beads in private collections or for sale.
Visits to various museums to view the items on display.