Linking epub/pdf, abandon simple navigation in favour of webhelp

Doc/lectures.xml

@@ -78,13 +78,6 @@
         help</productname> format.</para>
       </listitem>
 
-      <listitem xml:id="prefaceFormatHtmlSimplified">
-        <para><link
-        xlink:href="https://freedocs.mi.hdm-stuttgart.de/mobil">Online
-        documentation providing simplified navigation</link> suitable for
-        (some?) tablet readers.</para>
-      </listitem>
-
       <listitem xml:id="prefaceFormatEpub">
         <para><filename
         xlink:href="https://freedocs.mi.hdm-stuttgart.de/webhelp/lectures.epub">lectures.epub</filename>
@@ -96,16 +89,16 @@
         <caution>
           <para>Since <productname
           xlink:href="https://en.wikipedia.org/wiki/EPUB">Epub</productname>
-          readers do not (yet) support <xref linkend="glo_EPUB"/> 3.0 both formulas
-          and <xref linkend="glo_SVG"/> images have been converted to <xref
-          linkend="glo_PNG"/> files. This may account for poor image
+          readers do not (yet) support <xref linkend="glo_EPUB"/> 3.0 both
+          formulas and <xref linkend="glo_SVG"/> images have been converted to
+          <xref linkend="glo_PNG"/> files. This may account for poor image
           quality.</para>
         </caution>
       </listitem>
 
       <listitem xml:id="prefaceFormatPdf">
         <para><filename
-        xlink:href="https://freedocs.mi.hdm-stuttgart.de/webhelp/printversion.pdf">printversion.pdf</filename>
+        xlink:href="https://freedocs.mi.hdm-stuttgart.de/webhelp/lectures.pdf">printversion.pdf</filename>
         featuring the <xref linkend="glo_PDF"/> format (hopefully) providing
         improved printout typography.</para>