
http://www.esf.be/new/wp-content/uploads/2018/07/ESF-Press-Release-on-Importance-of-Services-Trade-in-EU-UK-Future-Relastionship.pdf

http://www.europarl.europa.eu/RegData/etudes/IDAN/2017/599352/EPRS_IDA%282017%29599352_EN.pdf

http://www.cesifo-group.de/ifoHome/publications/working-papers/CESifoWP/CESifoWPdetails?wp_num=6430&CESifoWP.search=+