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Critics have subjected Casablanca to many different readings. William Donelley, in his Love and Death in Casablanca, argues that Rick's relationship with Sam, and subsequently with Renault, is, "a standard case of the repressed homosexuality that underlies most American adventure stories".[22] Harvey Greenberg presents a Freudian reading in his The Movies on Your Mind, in which the transgressions which prevent Rick from returning to the US constitute an Oedipus complex, which is resolved only when Rick begins to identify with the father figure of Laszlo and the cause which he represents.[23] Sidney Rosenzweig argues that such readings are reductive, and that the most important aspect of the film is its ambiguity, above all in the central character of Rick; he cites the different names which each character gives Rick (Richard, Ricky, Mr Rick, Herr Blaine and so on) as evidence of the different meanings which he has for each person.[24]