The theory is attributed to J. Olivier of Saint Rémy de Provence, see for example, Lubin, Albert J. (1961). 'Vincent Van Gogh's Ear' in the Psychoanalytic Quarterly, 30:351-384, and by the same author Stranger on the earth: A psychological biography of Vincent van Gogh, Holt, Rinehart, and Winston, 1972. ISBN 0-03-091352-7, page 158. The substance of the theory is described in a 1951 letter to V. W. van Gogh (the artist's nephew) ... letter A13