Analysis of information sources in references of the Wikipedia article "Brexit and the Irish border" in English language version.
a leaked official UK government document has warned [..] that EU tariffs on goods entering Ireland "will severely disrupt trade," forcing some businesses to close or relocate
The Joint Statement and the accompanying Memorandum of Understanding on visa data exchange was signed by Minister for Justice, Equality and Defence, Alan Shatter, T.D. and UK Immigration Minister, Damien Green, M.P., in Dublin today
a hard border [..] is a frontier monitored and protected by customs officials and border inspectors, and potentially police or military personnel if there are security issues around the border
April 1923: The Irish Free State introduces customs controls which remain until 1993 and the creation of the Single Market