diff --git a/Doc/Sd1/arrays.xml b/Doc/Sd1/arrays.xml
index 2895c746f9210e8ff6fef1e4f1174b08c6f10149..c37b6f4741dfa57a3d51f6a2ac87985d0ee9079b 100644
--- a/Doc/Sd1/arrays.xml
+++ b/Doc/Sd1/arrays.xml
@@ -33,7 +33,7 @@
       <listitem>
         <para>Generate Comma separated list:</para>
 
-        <screen>Karen Smith, John Duncan, Paul Jacobs, Suzanne Enders, Peter Phillips        </screen>
+        <screen>Karen Smith, John Duncan, Paul Jacobs, Suzanne Enders, Peter Phillips</screen>
       </listitem>
 
       <listitem>
@@ -44,7 +44,7 @@
   &lt;li&gt;John &lt;emph&gt;Duncan&lt;/emph&gt;&lt;/li&gt;
   &lt;li&gt;Paul &lt;emph&gt;Jacobs&lt;/emph&gt;&lt;/li&gt;
   &lt;li&gt;Suzanne &lt;emph&gt;Enders&lt;/emph&gt;&lt;/li&gt;
-  &lt;li&gt;Peter &lt;emph&gt;Phillips&lt;/emph&gt;&lt;/li&gt;     
+  &lt;li&gt;Peter &lt;emph&gt;Phillips&lt;/emph&gt;&lt;/li&gt;
 &lt;/ul&gt;</programlisting>
       </listitem>
     </itemizedlist>
@@ -735,7 +735,7 @@ StringBuffer[]: [Ljava.lang.StringBuffer;</screen>
 
     <programlisting language="java">public static void main(String[] args) {
   final int [] lectures = new int[3]; // Three lectures
-  fill(lectures, 25); // Default lecture having 25 participants     
+  fill(lectures, 25); // Default lecture having 25 participants
   System.out.println("Second lecture has got " + lectures[1] +
           " participants");
 }
@@ -817,7 +817,7 @@ sort|toString: [Aaron, Eve, Mandy, Paul]</screen>
 // Precondition: Array must be ordered!
 ...println("sort|find(Mand): " + Arrays.binarySearch(names, "Mand"));
 ...println("sort|find(Mandy): " + Arrays.binarySearch(names, "Mandy"));
-...println("sort|find(Mandyer): " + Arrays.binarySearch(names, "Mandyer"));               </programlisting>
+...println("sort|find(Mandyer): " + Arrays.binarySearch(names, "Mandyer"));</programlisting>
 
       <para>Result:</para>
 
@@ -1077,12 +1077,11 @@ static String[] append (final String[] values, final String newValue) {
     <figure xml:id="sd1_array_fig_manualExtendArrayResult">
       <title>Extension result</title>
 
-      <programlisting language="none">  String[] member = {"Eve", "John", "Peter", "Jill"};
-  System.out.println("Original array: " + Arrays.toString(member));
-  final String <emphasis role="red">newMember</emphasis> = "<emphasis
-          role="red">Ernest</emphasis>";
-  member = append(member, <emphasis role="red">newMember</emphasis>);
-  System.out.println("Extended array: " + Arrays.toString(member));</programlisting>
+      <programlisting language="none">final String[] member = {"Eve", "John", "Peter", "Jill"};
+System.out.println("Original array: " + Arrays.toString(member));
+final String <emphasis role="red">newMember</emphasis> = "<emphasis role="red">Ernest</emphasis>";
+member = append(member, <emphasis role="red">newMember</emphasis>);
+System.out.println("Extended array: " + Arrays.toString(member));</programlisting>
 
       <screen>Original array: [Eve, John, Peter, Jill]
 Extended array: [Eve, John, Peter, Jill, <emphasis role="red">Ernest</emphasis>]</screen>
diff --git a/Doc/Sdi/docker.xml b/Doc/Sdi/docker.xml
index 00adbbaaf2213f9bdf16d4f94b13f06215ff934c..7b7d659b84b9ef376a4168008fb7976aca03fc85 100644
--- a/Doc/Sdi/docker.xml
+++ b/Doc/Sdi/docker.xml
@@ -21,21 +21,20 @@
       </listitem>
 
       <listitem>
-        <para><link xlink:href="???">Docker Cheat Sheet</link></para>
+        <para><link
+        xlink:href="https://github.com/wsargent/docker-cheat-sheet">Docker
+        Cheat Sheet</link></para>
       </listitem>
     </itemizedlist>
   </figure>
 
-  <figure xml:id="sdiDocker_figPullImage">
-    <title>Pull image using <xref linkend="glo_CLI"/></title>
+  <figure xml:id="sdiDocker_Hub">
+    <title>Docker hub</title>
 
-    <screen>&gt; <link
-        xlink:href="https://docs.docker.com/engine/reference/commandline/image_pull">docker image pull</link> alpine
-Using default tag: latest
-latest: Pulling from library/alpine
-<emphasis role="red">ff3a5c916c92</emphasis>: Pull complete 
-Digest: sha256:7df6db5aa61ae9480f52f0b3a06a140ab98d427f86d8d5de0bedab9b8df6b1c0
-Status: Downloaded newer image for alpine:latest</screen>
+    <para>Repository hosting publicly available Docker images: </para>
+
+    <para><uri
+    xlink:href="https://hub.docker.com/explore">https://hub.docker.com/explore</uri></para>
   </figure>
 
   <figure xml:id="sdiDocker_figSearchImages">
@@ -57,6 +56,18 @@ ownyourbits/nextcloudpi    NextCloud ARM …  7
 ...                     </screen>
   </figure>
 
+  <figure xml:id="sdiDocker_figPullImage">
+    <title>Pull image using <xref linkend="glo_CLI"/></title>
+
+    <screen>&gt; <link
+        xlink:href="https://docs.docker.com/engine/reference/commandline/image_pull">docker image pull</link> alpine
+Using default tag: latest
+latest: Pulling from library/alpine
+<emphasis role="red">ff3a5c916c92</emphasis>: Pull complete 
+Digest: sha256:7df6db5aa61ae9480f52f0b3a06a140ab98d427f86d8d5de0bedab9b8df6b1c0
+Status: Downloaded newer image for alpine:latest</screen>
+  </figure>
+
   <figure xml:id="sdiDocker_figPullNextcloudImage">
     <title>Pull <productname>Nextcloud</productname> image</title>
 
@@ -129,7 +140,7 @@ Status: Downloaded newer image for wonderfall/nextcloud:latest</screen>
 
     <screen>&gt; curl 'https://registry.hub.docker.com/v2/repositories/library/<emphasis
         role="red">nextcloud</emphasis>/tags/'|\
-      jq '."results"[]["name"]'
+      jq '."results"[]["name"]'  <emphasis role="red"># requires »aptitude install curl jq«</emphasis>
   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                  Dload  Upload   Total   Spent    Left  Speed
 100 11856    0 11856    0     0  11856      0 --:--:-- --:--:-- --:--:-- 20371