European Commission : Directorate-General for Economic and Financial Affairs., Turrini, A. 1., Roger, W., Havik, K., & McMorrow, K. (2008). The EU- US total factor productivity gap: An industry perspective. Brussels: Office for Infrastructure and Logistics in Brussels.

European Commission : Directorate-General for Economic and Financial Affairs., Alessandro 1966- Turrini, Werner Roger, Karel Havik, and Kieran McMorrow. The EU- US Total Factor Productivity Gap: An Industry Perspective. Brussels: Office for Infrastructure and Logistics in Brussels, 2008.

European Commission : Directorate-General for Economic and Financial Affairs., et al. The EU- US Total Factor Productivity Gap: An Industry Perspective. Brussels: Office for Infrastructure and Logistics in Brussels, 2008.