Cooper, Douglas in: Dictionary of Art Historians: „Daniel Catton Rich exposed Cooper of plagiarizing Rich's book on Douanier Rousseau (1942), in an article on the artist in the Burlington Magazine. After Cooper's caustic review of a book on Seurat by John Rewald (q.v.) in 1944, the author noticed similar parallels between his disparaged book and Cooper's 1946 Georges Seurat: Une baignade. Though the matter was settled without official acknowledgement, Cooper had to admit culpability.“ Abgerufen am 19. August 2010.
Cooper, Douglas, in: Dictionary of Art Historians: „Cooper certainly had flexible ethics.“ Abgerufen am 19. August 2010.
Cooper, Douglas In: Dictionary of Art Historians: „Cooper possessed an obstreperous personality, cultivating quarrels as much as friends. The French minister of culture became so jealous of Cooper's collection he refuse to allow the collection to France without Cooper donating some paintings to country.“ Abgerufen am 19. August 2010.
Rothenstein, John In: Dictionary of Art Historians, abgerufen am 21. August 2010; The Sorcerer’s Apprentice. S. 158–164.