diff --git a/docs_src/gitbuch.asciidoc b/docs_src/gitbuch.asciidoc
index e635e32..0d5c7f0 100644
--- a/docs_src/gitbuch.asciidoc
+++ b/docs_src/gitbuch.asciidoc
@@ -16,6 +16,8 @@ Valentin Haenel; Julius Plenz
 // :appendix-refsig: App.
 
 
+include::gitbuch_custom-attributes.adoc[]
+
 :leveloffset: +1
 
 // "vorwort.txt"          ->  Preface
diff --git a/docs_src/gitbuch_custom-attributes.adoc b/docs_src/gitbuch_custom-attributes.adoc
new file mode 100644
index 0000000..7fde64a
--- /dev/null
+++ b/docs_src/gitbuch_custom-attributes.adoc
@@ -0,0 +1,14 @@
+// *****************************************************************************
+// *                                                                           *
+// *                      CUSTOM ATTRIBUTES DEFINITIONS                        *
+// *                                                                           *
+// *****************************************************************************
+// Used for substitutions...
+
+// HTML Characters Entities
+// ========================
+// These provide human readable substitution which are safe to use on all output
+// formats (named character references are unsafe with formats like PDF)
+:en-dash: –
+
+// EOF //