The eye, the needle and the camel: Rich countries can benefit from EU membership (Nauro F. Campos, Fabrizio Coricelli, Luigi Moretti, VOX)

One common concern about membership of the EU is the notion that poorer members have more to gain than richer ones. This column focuses on the countries that joined the EU in 1973 (Denmark, UK and Ireland) and in 1995 (Austria, Finland and Sweden). The authors estimate that these rich countries benefited substantially from joining the EU. Furthermore, while the benefits from EU membership to poorer countries tend to be mostly in terms of per capita income, for richer countries the benefits tend to be mostly in terms of productivity.

http://voxeu.org/article/how-rich-nations-benefit-eu-membership