Analysis of information sources in references of the Wikipedia article "Diner" in Danish language version.
... Greeks became a visible presence in the diner and coffee shop business in the late 1950s after several waves of immigration. They congregated largely on the East Coast, where the food service industry provided an easy economic foothold for many immigrants who were often unskilled and unable to speak English. As with immigrants from many nations, one relative would send word of opportunity back home, encouraging others to come to America.
... Greeks became a visible presence in the diner and coffee shop business in the late 1950s after several waves of immigration. They congregated largely on the East Coast, where the food service industry provided an easy economic foothold for many immigrants who were often unskilled and unable to speak English. As with immigrants from many nations, one relative would send word of opportunity back home, encouraging others to come to America.