“…Finally, a work similar to our is a recent paper of Herwartz and Siedenburg (2011) which test convergence of ination dierentials in the monetary union using monthly relative normalized ULC indices for the manufacturing sector only from the IMF's international nancial statistics, for Austria, Belgium, Finland, France, Germany, Ireland, Italy, and Spain. Similarly to ours, they use manufacturing sector data, interpreting ULC ination dierentials in this sector as a direct indicator of the relative evolution of external competitiveness within the monetary union.…”