The discovery of the hidden Van Gogh was made when experts at the National Galleries of Scotland X-rayed the work.
Hidden Self-Portrait Discovered Beneath Van Gogh Painting –
Hidden Van Gogh self-portrait found behind another painting
Before and after: X-ray paintings by Picasso, Van Gogh to reveal their surprising stories - ABC News
Hidden Van Gogh self-portrait found behind painting in Scotland
New Van Gogh self-portrait discovered hidden under another painting, Van Gogh
Exploring Vincent van Gogh's Self Portrait with Bandaged Ear
Van Gogh Self Portrait Sparks Controversy - Artlyst
Van Gogh self-portrait (1889) - Wikipedia
Van Gogh self-portrait discovered on back side of another painting
Hidden Self-Portrait Discovered Beneath Van Gogh Painting
Vincent van Gogh: Hidden self-portrait discovered by X-ray