Gaston Leroux (2016). “The Phantom of the Opera & The Mystery of the Yellow Room (Mystery Classics): The Ultimate Gothic Romance Mystery and One of the First Locked-Room Crime Mysteries”, p.105, e-artnow
Gaston Leroux (2016). “The Phantom of the Opera & The Mystery of the Yellow Room (Mystery Classics): The Ultimate Gothic Romance Mystery and One of the First Locked-Room Crime Mysteries”, p.10, e-artnow
Gaston Leroux (2016). “GOTHIC CRIME MYSTERIES – Premium Collection: The Phantom of the Opera, The Mystery of the Yellow Room, The Secret of the Night, The Man with the Black Feather & Balaoo: Thriller Classics”, p.941, e-artnow