\noindent
\begin{center}
\begin{tabular}{|l|c|l|}
\hline
\multicolumn{3}{|c|}{{\vrule height12pt width0pt depth3.5pt\Large
Standard MM String Registers}}\\ 
\hline\hline
register&	 supported&\multicolumn{1}{|c|}{description}\\
\hline
BU&		x&	Bullet-character\\
Ci&		&	table-of-contents-indent-list\\
DT&		x&	date\\
EM&		x&	em-dash\\
F&		x&	footnont-numberer\\
HF&		&	heading-font-list\\
HP&		&	heading-point-size-list\\
Le&		&	Title for List of Equations\\
Lf&		&	Title for List of Figures\\
Lt&		&	Title for List of Tables\\
Lx&		&	Title for List of Exhibits\\
RE&		&	SCCS release level of mm\\
Rf&		x&	reference numberer\\
Rp&		&	title for references\\
Tm&		x&	trademark string\\
\hline\hline
x&\multicolumn{2}{|l|}{implemented}\\
p&\multicolumn{2}{|l|}{partially implemented; not all options available}\\
?&\multicolumn{2}{|l|}{implemented but effect is not fully standard}\\
\hline
\end{tabular}
\end{center}
\medskip