Spon, S. d. (1978). Supplement to History of the barons de Spon, comtes zu Forbach and allied families.
Chicago-Zitierstil (17. Ausg.)Spon, Seymour de. Supplement to History of the Barons De Spon, Comtes Zu Forbach and Allied Families. [S.l.], 1978.
MLA-Zitierstil (8. Ausg.)Spon, Seymour de. Supplement to History of the Barons De Spon, Comtes Zu Forbach and Allied Families. 1978.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.