Note 188 — IV On the Use of Engraved and Carved Gems as Talismans
Reading edition
Dissert. apol. de quibusdam Alexandri Severi numismat., p. 59. Cited in Dictionnaire de l’arch. chrét., vol. i, Pt. II, Paris, 1907, cols. 1789, 1790, where the amulet is figured.