This doctoral thesis consists in three chapters investigating cross-country linkages in different samples of industrialized economies. The first chapter shows that the share of the investment cycle's variance due to common international factors has increased in the United States as well in large European countries. The second chapter estimates the impact of the liberalization and internationalization of the financial and banking sectors on real GDP growth comovements. Since the late 1970s, a common international factor has contribued to most economic growth in th EU countries, the United States, Canada and Japan. Among several financial, bank and monetary indicators, equity prices, followed by portofolio investment have been by far the main drivers of this factor. The removal of controls on domestic credit emerges as the only financial liberalization policy measure with a large and negative effect on common growth before 1995. The third chapter investigates the sources of real GDP's comovements between the founding member states of the euro area. Throughout EMU, real cyclical synchronization was robustly linked to disparities in term of fiscal policy and of total factor productivity gains. Cyclical synchronization was closely related to similarities in unit labour cost growth before 2007, but not after 2007 when long-term interest rate differentials became a major cause of cyclical divergence.