diff --git a/doc/latex_sty/xtab.sty b/doc/latex_sty/xtab.sty
new file mode 100644
index 0000000000000000000000000000000000000000..9eb86645028600a37705ebf03aa913172c728394
--- /dev/null
+++ b/doc/latex_sty/xtab.sty
@@ -0,0 +1,75 @@
+%%
+%% This is file `stdclsdv.sty',
+%% generated with the docstrip utility.
+%%
+%% The original source files were:
+%%
+%% stdclsdv.dtx  (with options: `usc')
+%% 
+%%  Copyright 1999 Peter R. Wilson
+%% 
+%%  This program is provided under the terms of the
+%%  LaTeX Project Public License distributed from CTAN
+%%  archives in directory macros/latex/base/lppl.txt.
+%% 
+%% Author: Peter Wilson (CUA and NIST)
+%%         now at: peter.r.wilson@boeing.com
+%% 
+\NeedsTeXFormat{LaTeX2e}
+\ProvidesPackage{stdclsdv}[1999/01/18 v1.0 Sectional divisions]
+\newif\ifSCDknownclass\SCDknownclassfalse
+\newif\ifSCDpart\SCDparttrue
+\newif\ifSCDchapter\SCDchapterfalse
+\newif\ifSCDsection\SCDsectiontrue
+\newif\ifSCDnodivs\SCDnodivsfalse
+\@ifclassloaded{book}{\SCDknownclasstrue\SCDchaptertrue}{}
+\@ifclassloaded{report}{\SCDknownclasstrue\SCDchaptertrue}{}
+\@ifclassloaded{article}{\SCDknownclasstrue}{}
+\@ifclassloaded{proc}{\SCDknownclasstrue}{}
+\@ifclassloaded{ltxdoc}{\SCDknownclasstrue}{}
+\@ifclassloaded{slides}{\SCDknownclasstrue
+                        \SCDnodivstrue\SCDpartfalse\SCDsectionfalse}{}
+\@ifclassloaded{letter}{\SCDknownclasstrue
+                        \SCDnodivstrue\SCDpartfalse\SCDsectionfalse}{}
+\ifSCDknownclass\else
+  \SCDnodivstrue
+  \ifx\part\undefined
+    \SCDpartfalse
+  \else
+    \SCDnodivsfalse
+  \fi
+  \ifx\chapter\undefined\else
+    \SCDchaptertrue \SCDnodivsfalse
+  \fi
+  \ifx\section\undefined
+    \SCDsectionfalse
+  \else
+    \SCDnodivsfalse
+  \fi
+\fi
+\newcommand{\SCDquit}{}
+\newif\ifSCDSameDefinition
+\def\SCDCheckCommand{\@star@or@long%
+  \SCDSameDefinitiontrue%             changed from CheckCommand
+  \@SCD@check@command}
+  \@onlypreamble\SCDCheckCommand
+\def\@SCD@check@command#1#2#{\@SCD@check@c#1{#2}}
+  \@onlypreamble\@SCD@check@command
+\long\def\@SCD@check@c#1#2#3{%
+  \expandafter\let\csname\string\reserved@a\endcsname\relax
+  \renew@command\reserved@a#2{#3}%
+  \@ifundefined{\string\reserved@a}%
+   {\@SCD@check@eq#1\reserved@a}%
+   {\expandafter\@SCD@check@eq
+    \csname\string#1\expandafter\endcsname
+    \csname\string\reserved@a\endcsname}}
+  \@onlypreamble\@SCD@check@c
+\def\@SCD@check@eq#1#2{%
+  \ifx#1#2\else
+    \SCDSameDefinitionfalse  % changed from CheckCommand
+  \fi}
+  \@onlypreamble\@SCD@check@eq
+\endinput
+%%
+%% End of file `stdclsdv.sty'.
+
