diff --git a/mathics/doc/common_doc.py b/mathics/doc/common_doc.py
index 3e0301954..189f5347f 100644
--- a/mathics/doc/common_doc.py
+++ b/mathics/doc/common_doc.py
@@ -15,18 +15,40 @@
 
 
 from mathics.doc.doc_entries import (
+    ALLOWED_TAGS,
+    ALLOWED_TAGS_RE,
+    CONSOLE_RE,
+    DL_ITEM_RE,
+    DL_RE,
+    HYPERTEXT_RE,
+    IMG_PNG_RE,
+    IMG_RE,
+    LATEX_RE,
+    LIST_ITEM_RE,
+    LIST_RE,
+    MATHICS_RE,
+    PYTHON_RE,
+    QUOTATIONS_RE,
+    REF_RE,
+    SPECIAL_COMMANDS,
     DocTest,
     DocTests,
     DocText,
     DocumentationEntry,
     Tests,
+    get_results_by_test,
     parse_docstring_to_DocumentationEntry_items,
+    post_sub,
+    pre_sub,
 )
 
 gather_tests = parse_docstring_to_DocumentationEntry_items
 XMLDOC = DocumentationEntry
 
 from mathics.doc.structure import (
+    MATHICS3_MODULES_TITLE,
+    SUBSECTION_END_RE,
+    SUBSECTION_RE,
     DocChapter,
     DocGuideSection,
     DocPart,
@@ -34,4 +56,5 @@
     DocSubsection,
     Documentation,
     MathicsMainDocumentation,
+    sorted_chapters,
 )
diff --git a/mathics/doc/doc_entries.py b/mathics/doc/doc_entries.py
index 1d423d1dd..4c543addc 100644
--- a/mathics/doc/doc_entries.py
+++ b/mathics/doc/doc_entries.py
@@ -84,7 +84,6 @@
     "Wolfram": (r"<em>Wolfram</em>", r"\emph{Wolfram}"),
     "skip": (r"<br /><br />", r"\bigskip"),
 }
-SUBSECTION_END_RE = re.compile("</subsection>")
 
 
 TESTCASE_RE = re.compile(
diff --git a/mathics/doc/structure.py b/mathics/doc/structure.py
index 06508c8d1..70622a535 100644
--- a/mathics/doc/structure.py
+++ b/mathics/doc/structure.py
@@ -32,7 +32,7 @@
 CHAPTER_RE = re.compile('(?s)<chapter title="(.*?)">(.*?)</chapter>')
 SECTION_RE = re.compile('(?s)(.*?)<section title="(.*?)">(.*?)</section>')
 SUBSECTION_RE = re.compile('(?s)<subsection title="(.*?)">')
-
+SUBSECTION_END_RE = re.compile("</subsection>")
 
 # Debug flags.