Tait, 39; Cherry, 27–28, con fotografie online here, da Richard II's Treasure; the Riches of a Medieval King, da Institute of Historical Research and Royal Holloway, University of London.
Evans, Joan. "The Duke of Orléans' Reliquary of the Holy Thorn", 1941, The Burlington Magazine for Connoisseurs, Vol 78, issue 459, pp 196, 200–201 JSTOR
