PUBLIC DOMAIN MARK 1.0 (C) NATIONAL TRUST, FENTON HOUSE; SUPPLIED BY THE PUBLIC CATALOGUE FOUNDATION). ILLUSTRATION BY BRIAN STAUFFER SOURCES: "FACE VALUES," BY DORIS Y. TSAO, IN SCIENTIFIC AMERICAN, VOL. 320, NUM. 2; FEBRUARY 2019. BY UNKNOWN ARTIST; UPLOADED TO WIKIPEDIA BY SILVERWHISTLE - RICHARD III SOCIETY WEBSITE VIA ENGLISH WIKIPEDIA, PUBLIC DOMAIN.
