A later writer, such as Leijonhufvud, I knew to have it wrong, when he later argued the merits of Keynes's subtle intuitions and downplayed the various (identical!) mathematical versions of The General Theory. The so-called 1937 Hicks or later Hicks–Hansen IS–LM diagram will do as an example for the debate.

New millennium - An Interview with Paul A. Samuelson, 2003