can someone refer me some good sources of the rise of Islamic extremists?

Dear comrades, I had a family BBQ yesterday and my beloved uncle is under the Impression that all Muslim extremists (Al Qaeda, Isis and such) are Iran's fault and that they are the making of Shia Islam. That the Sunni are western Muslims oppressed by Iran.

Are there any documentaries or articles I could use to inform him?

I tried explaining operation Cyclone and timber sycamore but Wikipedia usually isn't that convincing in his circle (he has a PhD in engineering and used to work for a western oil company in the middle east)