http://unctad.org/en/PublicationsLibrary/wir2017_en.pdf
https://www.auswaertiges-amt.de/blob/2608580/49d50fecc479304c3da2e2079c55e106/china-strategie-en-data.pdf
https://www.nao.org.uk/wp-content/uploads/2018/01/Implementing-the-UKs-exit-from-the-European-Union-the-Deparment-for-International-Trade.pdf