- http://ie.microsoft.com/testdrive/Graphics/hands-on-css3/hands-on_flex.htm
- https://msdn.microsoft.com/en-us/library/ie/bg124109(v=vs.85).aspx
- http://codepen.io/chriswrightdesign/pen/emQNGZ
- http://codepen.io/liquidbook/pen/OPGBKx — headway extra code
- http://codepen.io/liquidbook/pen/zxXmgV — stripped
- http://davidwalsh.name/css-vertical-center-flexbox
- http://codepen.io/liquidbook/pen/WbWYja
- http://timhettler.github.io/compass-flexbox/
- http://the-echoplex.net/flexyboxes/
- http://philipwalton.com/articles/normalizing-cross-browser-flexbox-bugs/