A short research report by the London-based ICSR, the author being Aaron Y. Zelin, from the DC-based WINEP:http://icsr.info/2013/04/icsr-insigh...rs-in-syria-2/

It shows that the extent to which the Syrian conflict has mobilised Muslims across the world is significant: between 140 and 600 Europeans have gone to Syria since early 2011, representing 7-11 per cent of the foreign fighter total. (Much later) The extent to which the Syrian conflict has mobilised Muslims across the world is significant and may be compared to the conflicts in Iraq in the 2000s, Bosnia in the 1990s, and Afghanistan in the 1980s.