Robert N. Anderson of the San Jose State University Materials Engineering Department has developed a nondestructive method of dating copper alloys by means of their electrical conductivity. If this method proves reliable, it may be possible to directly date the bracelets themselves. Gisela M. A. Richter, Greek, Etruscan and Roman Bronzes (New York: Metropolitan Museum of Art, 1915), pp. 336–339, shows examples of similar bracelets, but notes that these simple types were in use for long periods of time.