Fixed tutorial links, especially to external pages
diff --git a/templates/doc/korap/krill.html.ep b/templates/doc/korap/krill.html.ep
index cb013c0..9e10159 100644
--- a/templates/doc/korap/krill.html.ep
+++ b/templates/doc/korap/krill.html.ep
@@ -6,6 +6,6 @@
<p><strong>Main developer:</strong> Nils Diewald, Eliza Margaretha</p>
-<p>Krill is a <a href="https://lucene.apache.org/">Lucene</a> based search engine for large annotated corpora, used as a backend component for KorAP. It is the reference implementation for <%= doc_link_to('KoralQuery', 'api', 'koralquery') %>, covering most of the protocols features.</p>
+<p>Krill is a <%= doc_ext_link_to 'Lucene', "https://lucene.apache.org/" %> based search engine for large annotated corpora, used as a backend component for KorAP. It is the reference implementation for <%= doc_link_to('KoralQuery', 'api', 'koralquery') %>, covering most of the protocols features.</p>
-<p>Krill is open source and available on <a href="https://github.com/KorAP/Krill">GitHub</a>.</p>
+<p>Krill is open source and available on <%= doc_ext_link_to 'GitHub', "https://github.com/KorAP/Krill" %>.</p>