1. L. Engen , Het Glas in Belgïe, Mercatorfonds, Antwerp1989, pp. 121–133
2. C. Mortimer , in Trade and Discovery: the Scientific Study of Artefacts from Post-Medieval Europe and Beyond, Occasional Paper 109, ed. D. R. Hook and D. R. M. Gaimster, British Museum Press, London, 1995