1. https://royalsociety.org/events/2014/04/bio-nano
2. http://history.evonik.com/sites/geschichte/en/inventions/aerosil/pages/default.aspx
3. European Commission Joint Research Centre Synthetic Amorphous Silicon Dioxide (NM-200, NM-201, NM-202, NM-203, NM-204): Characterisation and Physico-Chemical Properties. JRC Scientific and Policy Reports, JRC 83506 (Publications Office of the European Union, 2013).
4. Code of Federal Regulations Title 21, Vol. 3, 21CFR172.480 (US FDA, 2013);
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?fr=172.480
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http://go.nature.com/2BmLc1