http://trade.ec.europa.eu/doclib/docs/2018/october/tradoc_157469.pdf
http://www.chinese-embassy.org.uk/eng/ambassador/t1720992.htm
https://www.cesifo-group.de/DocDL/ifoDD_18-01_29-31_Achten.pdf
https://insightcrime.org/investigations/synthetic-silk-road-tracing-china-grey-market-precursor-chemical-trade/