Attig et al (2013)

Attig, Najah, Narjess Boubakri, Sadok El Ghoul, and Omrane Guedhami.  "International Diversification and Corporate Social Responsibility.”  Working paper (Saint Mary’s University, Halifax), 2013.

From the authors' abstract:  "Using a large sample of 3,040 U.S. firms and 16,606 firm-year observations over the 1991-2010 period, we find strong evidence that firm internationalization is positively related to the firm’s corporate social responsibility (CSR) rating."