Some great references of the HTML5 specification online:
HTML5 – Edition for Web Authors (https://dev NULL.w3 NULL.org/html5/spec-author-view/)
HTML5 – A vocabulary and associated APIs for HTML and XHTML (https://www NULL.w3 NULL.org/TR/html5#auto-toc-1)
HTML5 Outliner – gsnedders.html5.org/outliner/ (https://gsnedders NULL.html5 NULL.org/outliner/)
HTML5 Outliner – h5o (bookmarklet, Chrome extension) (https://code NULL.google NULL.com/p/h5o/)
Your Ultimate Guide to the Rel Attribute in HTML5 (https://webtapmagazine NULL.com/2010/09/21/your-ultimate-guide-to-the-rel-attribute-in-html5/)
For more reference, please check out the course name: HTML5: Structure, Syntax, and Semantics from the link of Lynda.com below.
(https://www NULL.lynda NULL.com/home/otl NULL.aspx?utm_medium=affiliate&utm_source=ldc_affiliate&utm_content=42&utm_campaign=CD3404&bid=42&aid=CD3404&opt=)
HTML5: Structure, Syntax, and Semantics gives designers a deeper understanding of HTML5 and shows how to create richer, more meaningful web pages with structural tags and descriptive attributes. Author James Williamson presents an overview of HTML5 and its development, defines the new tags and attributes, and discusses how browsers parse and display HTML5 content. The course also includes step-by-step instructions for constructing an HTML5 document with a header and footer, navigation, content groups, and formatting. Exercise files are included with the course.
Defining basic elements
Exploring the content model
Creating document sections
Using hgroup to override sectioning
Using the proper nesting structure
Choosing the right structural element
Using class and ID attributes
Grouping content with asides
Using divs in HTML5
Creating block level links
Defining link relationships
Understanding current browser support
Adding support for elements in older browsers
Following is a list of known implementations of HTML5 and related features in web browsers.
Implementations in Web browsers (https://wiki NULL.whatwg NULL.org/wiki/Implementations_in_Web_browsers)
Comparison of layout engines (HTML5) (https://en NULL.wikipedia NULL.org/wiki/Comparison_of_layout_engines_%28HTML5%29)
browser support revealed (https://findmebyip NULL.com/litmus)
Windows Internet Explorer Testing Center (https://samples NULL.msdn NULL.microsoft NULL.com/ietestcenter/)
When can I use… (https://caniuse NULL.com/)
Compatibility tables for support of HTML5, CSS3, SVG and more in desktop and mobile browsers.
html5test.com (https://html5test NULL.com/)
How well does your browser support HTML5?
HTML5 accessibility (https://html5accessibility NULL.com/)
(https://www NULL.lynda NULL.com/home/dreamweaver NULL.aspx?utm_medium=affiliate&utm_source=ldc_affiliate&utm_content=546&utm_campaign=CD3404&bid=546&aid=CD3404&opt=)
Tutorials and Articles
dev.opera.com (https://dev NULL.opera NULL.com/articles/tags/open%20web/)
Internet Explorer Learning – HTML5 (https://msdn NULL.microsoft NULL.com/en-us/ie/aa740476)
The WHATWG Blog (https://blog NULL.whatwg NULL.org/)
html5 doctor (https://html5doctor NULL.com/)