cheat sheets.

<ELEMENT id="" class="" MORE_ATTR=""></ELEMENT>
  <ELEMENT /> for IMG, BR, META, LINK

<header>   --  belongs_to :section, :has_many :headlines(h#)
<nav>      --  belongs_to :section, :header, :footer
<section>  --  has_many :headers, :asides, :articles
<aside>    --  related_to :article
<article>  --  represents a :entry
<footer>   --  represents :copyright_data

Thanks to: http://orderedlist.com/resources/html-css/structural-tags-in-html5/