“…4 Such as the Stolper Samuelson effect -see, for example, Krugman (2000) on their relevance, or outsourcing modelsà la Feenstra and Hanson (2004). 5 Unel (2010) introduces heterogeneous firms in a framework similar to that of Epifani and Gancia (2008), but he concentrates on the reallocation of market shares between sectors as a driver of the skill premium. 6 See, for example, Clerides, Lach, and Tybout (1998), Bernard and Jensen (1999), Delgado, Farinas, and Ruano (2002).…”