The main source for the data on which Sassen based her talk:
Chapters 5, 6 and 7 of Cities in a World Economy, fully updated and revised 4th edition, 2012, Sage
Novel Spatial Formats: The Mega-Region and the Global City.
"When Cities Become Extreme Sites for Our Major", article by Saskia Sassen
"An Emergent Urban Geopolitics", article by Saskia Sassen, August 2012