Richard Lipsey developed it in a broader context, clarifying the adjustment function. Robert Solow and Paul Samuelson found that it also held in the United States and made it relevant to policymakers 
Richard Lipsey developed it in a broader context, clarifying the adjustment function. Robert Solow and Paul Samuelson found that it also held in the United States and made it relevant to policymakers by introducing mark-up pricing. Edmund Phelps and Milton Friedman questioned its stability in the long run, arguing that the government could not maintain a permanent tradeoff between the two quantities in question, disagreeing with the findings made in the article "Analytics of Anti-Inflation Policy" with their view of the natural-rate hypothesis.  FTP, name this relationship depicting the inverse relation between the rate of unemployment and the rate of change of money wages in a certain curve.
Richard Lipsey developed it in a broader context, clarifying the adjustment function.
Phillips curve