http://sass-lang.com
http://thesassway.com
http://en.wikipedia.org/wiki/Sass_(stylesheet_language)
http://www.sitepoint.com/getting-started-with-sass
http://thesassway.com/beginner/the-inception-rule
http://www.sitepoint.com/sassdoc-documentation-tool-sass
http://www.sitepoint.com/tips-help-level-up-sass