UI Guidelines

Microsoft User Interface Design Guidelines

http://msdn.microsoft.com/en-us/library/jj651618(v=nav.71).aspx

Ribbon - Microsoft

http://msdn.microsoft.com/en-us/library/windows/desktop/cc872782.aspx

Microsoft Inductive User Interface Guidelines

http://msdn.microsoft.com/en-us/library/ms997506.aspx

iOS Human Interface Guidelines

http://developer.apple.com/library/ios/#documentation/UserExperience/Conceptual/MobileHIG/Introduction/Introduction.html