Hello Weiqing,

I don't know if this has enough data regarding American media (newspapers):

Schwarz, K. (2014). Coverage of the Euro Crisis in Spanish, German, British, and American Elite Newspapers.

http://dc.uwm.edu/cgi/viewcontent.cgi?article=1380&context=etd

Very best wishes,

Mary

Trenz, Hans-Jörg (2004): Media Coverage on European Governance. Exploring

the European Public Sphere in National Quality Newspapers. In: European

Journal of Communication, 19 (3), 291-319.

I just know a publication in German about legitimacy discourses on international and supranational organisations (e. g. the EU). see: http://www.campus.de/buecher-campus-verlag/wissenschaft/politikwissenschaft/prekaere_legitimitaeten-3757.html

Maybe, the authors published their findings also in English?!

Additionally and as far as I know, the visibility of EU topics is relatively low in US media and therefore, it is hard to deal with strongly different media representation, media systems, etc. 9(if you try to compare the representation of the EU in different countries, for instance)

However, in a more quantitative, longitudinal design, you could address a really interesting topic by studying the EU representation in the US media...