The Porter readings present a number of useful concepts. But the reading by Gilbert and Strebel, two professors of strategy at the IMEDE business school in Lausanne, Switzerland, seems to knit them together in a unique way. Drawing on such Porter concepts as industry analysis, generic strategies, and strategic groups (including industry stage of development) , Gilbert and Strebel suggest an integrated framework to formulate strategy. They also include in their article something akin to the value chain theme of Porter's 1985 book, which they label the "business system."