See, Lee and Yang: The break-up

Jeremy Bernstein said, "when the thing came back, 'Lee and Yang' were changed to 'Yang and Lee'" which is kind of odd... "when the collaboration began, Lee was younger and a junior person and Yang was older, in a different social class in China." Also, he said, " I think Lee bagan getting most the ideas and Yang was gettimg most of the credits, and that's the source of their tension..."

Source,
http://www.webofstories.com/play/jeremy.bernstein/53