app/views/collections/_header.html.erb
<%= concept_header collection %>
<%= content_for :head do -%>
<link href="<%= rdf_url(collection.origin, :format => :ttl, :lang => nil) %>" type="text/turtle" rel="alternate" title=""/>
<link href="<%= rdf_url(collection.origin, :format => :rdf, :lang => nil) %>" type="application/rdf+xml" rel="alternate" title=""/>
<% end -%>