Atom and AtomPub

Primary resources

Atom Syndication Format (Atom)

Atom Publishing Protocol (AtomPub)

Hypertext Transfer Protocol (HTTP)

Representational State Transfer (REST)

Secondary resources

Atom Link Relations

It's about the rel attribute of atom:links:

<atom:link rel="alternate" type="text/html">http://example/resource.html</atom:link>
           -----=========-

MIME media type Directories of Content Types and Subtypes

It's about the type attribute of atom:links:

<atom:link rel="alternate" type="text/html">http://example/resource.html</atom:link>
                           -----==========-

OpenSearch Specification

Web Distributed Authoring and Versioning (WebDAV)

Tutorial resources

Visual Guide to Atom

Ruby on Rails related resources