As Geddes (2006: 166) has noted, security oriented approaches towards immigration at the EU - level pushed southern European countries to increasingly tighten external border controls. (blog.politics.ox.ac.uk)
Business leaders must also gauge a country's openness — the degree to which people, ideas, information, goods, and services flow freely in both directions across external borders and within the nation itself. (inc.com)
The signatory states to the agreement have abolished all internal borders in lieu of a single external border.» (businessinsider.com)