Jonathan Hughes: Somerset, Charles, first earl of Worcester (c.1460–1526). In: Henry Colin Gray Matthew, Brian Harrison (Hrsg.): Oxford Dictionary of National Biography, from the earliest times to the year 2000 (ODNB). Oxford University Press, Oxford 2004, ISBN 0-19-861411-X (doi:10.1093/ref:odnb/26004 Lizenz erforderlich), Stand: 2004
Jonathan Hughes: Somerset, Charles, first earl of Worcester (c.1460–1526). In: Henry Colin Gray Matthew, Brian Harrison (Hrsg.): Oxford Dictionary of National Biography, from the earliest times to the year 2000 (ODNB). Oxford University Press, Oxford 2004, ISBN 0-19-861411-X (doi:10.1093/ref:odnb/26004 Lizenz erforderlich), Stand: 2004