Replace rel="resource" by rel="prefetch"

Resource is not a valid keyword here, and prefetch seems to fit.

http://www.w3.org/html/wg/drafts/html/master/links.html#link-type-prefetch
<blockquote>4.12.5.9 Link type "prefetch"<br />
The prefetch keyword may be used with link, a, and area elements. This keyword creates an external resource link.<br />
The prefetch keyword indicates that preemptively fetching and caching the specified resource is likely to be beneficial, as it is highly likely that the user will require this resource.<br />
There is no default type for resources given by the prefetch keyword.</blockquote>