
http://blogs.lse.ac.uk/brexit/2018/05/15/switzerland-wanted-more-immigration-controls-but-economic-self-interest-will-probably-prevail/

http://www.cer.org.uk/sites/default/files/insight_js_st_9.6.17.pdf

https://insightcrime.org/investigations/synthetic-silk-road-tracing-china-grey-market-precursor-chemical-trade/