The following sources were consulted in the preparation of the article “10 historical figures who took secrets to the grave.”
- Death of the Man in the Iron Mask
- Fermat’s Last Theorem
- The Mystery of Edwin Drood
- Lee Harvey Oswald: Background and Possible Motives
- H.H. Holmes: The Victims of Chicago’s First Serial Murderer
- False Dmitry I
- 400 years later, accounts of Hungarian ‘Blood Countess’ remain shrouded in mystery and controversy
- Reading Into the Throne: On James Hampton’s Notebook
- What Killed Albert Einstein?
- Charles II and the Discovery of the ‘Princes in the Tower’ in 1674