Ernest Jones schreibt aus Zürich an Frieda Gross: "I found Jung very excited - could hardly speak - & very friendly. [...] In a few minutes he gave me quite an illuminating account of O. from a psycho-pathological point of view. I quite agree with his diagnosis. [...]"

Robinson, Ken: A Portrait of the Psychoanalyst as a Bohemian, in: Bachhiesl, Christian et al. (Eds.): Psychoanalyse & Kriminologie. Hans & Otto Gross. Libido und Macht. 8. Internationaler Otto Gross Kongress, Graz, 14. bis 16. Oktober 2011, S. 453