I think you can use data from Input-Output-Models for your analysis. There are several sources to obtain such data. Some are commercial (GTAP, https://www.gtap.agecon.purdue.edu/databases/v7/), some are free (WIOD, http://www.wiod.org/new_site/home.htm).

Dear @Stefano, let me bring some articles about USA and The Competitive Advantage of Nations, like Sweden, Italy...! Be back later! regards!

http://webcache.googleusercontent.com/search?q=cache:tkQiENk4OxIJ:https://hbr.org/1990/03/the-competitive-advantage-of-nations+&cd=5&hl=en&ct=clnk&gl=rs

http://www.nber.org/programs/pr/pr.html

I think you can use data from Input-Output-Models for your analysis. There are several sources to obtain such data. Some are commercial (GTAP, https://www.gtap.agecon.purdue.edu/databases/v7/), some are free (WIOD, http://www.wiod.org/new_site/home.htm).

Dear @Stefano, national specialization (i.e. production) can be expressed in form of the Herfindahl index. See the papers below for further hints. Rgards !!! 

http://eprints.ucl.ac.uk/18172/1/18172.pdf

http://www.fiw.ac.at/fileadmin/Documents/Publikationen/Working_Paper/N_062-Palan.pdf

Dear Stefano, you can get some ideas consulting papers on this link. Best regards!!!

http://www.tandfonline.com/toc/cres20/38/9#.VN7KNU10yAU

Hi Stefano, you can have a look to the enclosed article.

Regards,

Marco

Could it be otherwise:that non-specialization is the source of of productivity and hence trade? Especially intra-industry trade?

https://ideas.repec.org/a/inm/ormnsc/v49y2003i1p39-56.html

http://ec.europa.eu/economy_finance/publications/publication_summary14307_en.htm

As nations become richer, the change in their socioeconomic metabolism (from agricultural to industrial production) helps less to improve resource productivity than previously thought.

http://www.pnas.org/content/112/20/6271.full.pdf