Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Global trends in cross-border collaboration by international region: 1996–2014. Source: SCImago Journal and Country Rank based on Scopus (40). Notably, the curves for Western (W.) Europe and Eastern (E.) Europe are, before 2004, characterized by a roughly constant offset, thereby satisfying the prior equal slope condition of the DiD framework.
