LESS is MOAR
Introduction To Sass
BDUG Responsive Web Theming - 7/23/12
Sass and Compass - Getting Started
Forget Frameworks: Create Your Own Flexible Grid System
Fast Prototyping Strategies for UI design
Developing for Next Gen Identity Services
A Common API & UI for Building Next Generation Identity Services
LESS
What makes Sass so Syntactically Awesome?
Developer Guide: Turn Your Force.com Canvas App Into a Salesforce1 App
Logo Design Process by Nirvan
