An Interactive Guide to Flexbox in CSS
By far the best guide to Flexbox to date. I finally understand flex-basis.
The Flexbox Holy Albatross | HeydonWorks
Brilliant.
How Big Is That Box? Understanding Sizing In CSS Layout — Smashing Magazine
Leveling Up With Flexbox presentation at Smashing Conference
Internet Explorer 10 Developer Guide:CSS
Exciting reference, shame all properties are still vendor prefixed. "Internet Explorer 10 Developer Guide:CSS"