SOA Zytrax reference

Doc/Sdi/dns.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<chapter version="5.1" annotations="slide" xml:id="sdiDns" xmlns="http://docbook.org/ns/docbook"
+<chapter annotations="slide" version="5.1" xml:id="sdiDns"
+         xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink"
          xmlns:xila="http://www.w3.org/2001/XInclude/local-attributes"
          xmlns:xi="http://www.w3.org/2001/XInclude"
@@ -187,7 +188,9 @@ hdm-stuttgart.de.	3600	IN	NS	iz-net-2.hdm-stuttgart.de.</screen>
     <para>You may follow <quote
     xlink:href="https://www.linuxbabe.com/debian/authoritative-dns-server-debian-10-buster-bind9">Set
     Up BIND Authoritative DNS Server on Debian 10 Buster</quote> implementing
-    the subsequent steps.</para>
+    the subsequent steps. You may want to read <link
+    xlink:href="https://www.zytrax.com/books/dns/ch8/soa.html">Start of
+    Authority Resource Record</link> in particular.</para>
 
     <section xml:id="sdiDnsUseDig">
       <title>Querying <xref linkend="glo_DNS"/> data.</title>
@@ -205,7 +208,7 @@ hdm-stuttgart.de.	3600	IN	NS	iz-net-2.hdm-stuttgart.de.</screen>
       your <quote>a</quote> virtual machine. The MI department has already set
       up a <xref linkend="glo_DNS"/> service for
       <code>mi.hdm-stuttgart.de</code>. But regarding upcoming exercises we
-      want to be able configuring private host aliases. </para>
+      want to be able configuring private host aliases.</para>
 
       <para>Consider the example virtual machine
       <code>sdi4a.mi.hdm-stuttgart.de / 141.62.75.104</code> hosting a <xref