Who proposed the theory that foreign trade is the engine of economic growth?

The theory that foreign trade is the engine of economic growth was proposed by American economist Robertson in the 1930s, and is also known as the "growth engine" theory. In the 1950s, Knox further supplemented this theory based on his analysis of the causes of economic development in Britain and new immigrant areas in the 19th century. He believed that foreign trade was the driving force of economic growth.