\newcount\@secpenalty%
\@secpenalty = -300%
\newif\if@noskipsec%
\@noskipsectrue%
%
\def\@startsection#1#2#3#4#5#6{%
   \if@noskipsec%
       \leavevmode%
   \fi%
   \par%
   \@tempskipa #4\relax%
   \@afterindenttrue%
   \ifdim \@tempskipa < \z@%
       \@tempskipa -\@tempskipa%
       \@afterindentfalse%
   \fi%
   \if@nobreak%
       \everypar{}%
    \else%
       \addpenalty\@secpenalty%
       \addvspace\@tempskipa%
   \fi%
   \@ifstar%
       {\@ssect{#3}{#4}{#5}{#6}}%
       {\@dblarg{\@sect{#1}{#2}{#3}{#4}{#5}{#6}}}}%
%
%
\def\@sect#1#2#3#4#5#6[#7]#8{%
     \ifnum #2> \c@secnumdepth%
         \let\@svsec\@empty%
      \else%
         \refstepcounter{#1}%
         \protected@edef\@svsec{\@seccntformat{#1}\relax}%
     \fi%
     \@tempskipa #5\relax%
     \ifdim \@tempskipa > \z@%
         \begingroup 
             #6\relax%
             \@hangfrom{\hskip #3\relax\@svsec}%
             {\interlinepenalty \@M #8\par}%
        \endgroup%
       \csname #1mark\endcsname{#7}%
       \addcontentsline{toc}{#1}{%
                         \ifnum #2>\c@secnumdepth%
                          \else%
                              \protect\numberline{\csname the#1\endcsname}%
                         \fi%
                         #7}%
     \else%
        \def\@svsechd{#6%
                      \hskip #3\relax  %% \relax added 2 May 90
                      \@svsec #8\csname #1mark\endcsname%
                      {#7}%
                      \addcontentsline{toc}{#1}{%
                              \ifnum #2>\c@secnumdepth%
                               \else%
                                  \protect\numberline{\csname the#1\endcsname}%
                              \fi%
                              #7}}%
    \fi%
    \@xsect{#5}}%
%
\def\@xsect#1{%
    \@tempskipa #1\relax%
    \ifdim \@tempskipa>\z@%
        \par \nobreak%
        \vskip \@tempskipa%
        \@afterheading%
     \else%
        \global\@nobreakfalse%
        \global\@noskipsectrue%
        \everypar{\if@noskipsec%
                      \global\@noskipsecfalse%
                      \clubpenalty\@M%
                      \hskip -\parindent%
                      \begingroup 
                          \@svsechd 
                      \endgroup%
                      \unskip%
                      \@tempskipa #1\relax%
                      \hskip -\@tempskipa%
                   \else%
                      \clubpenalty \@clubpenalty%
                      \everypar{}%
                  \fi}%
    \fi%
    \ignorespaces}%
%
\def\@seccntformat#1{%
    \csname the#1\endcsname%
    \quad}%
%
\def\@ssect#1#2#3#4#5{%
    \@tempskipa #3\relax%
    \ifdim \@tempskipa > \z@%
        \begingroup%
            #4%
            \@hangfrom{\hskip #1}%
            {\interlinepenalty \@M #5\par}%
        \endgroup%
    \else%
       \def\@svsechd{#4\hskip #1\relax #5}%
   \fi%
   \@xsect{#3}}%
%
\newif\if@afterindent%
\@afterindenttrue%
%
\def\@afterheading{%
    \global\@nobreaktrue%
    \everypar{\if@nobreak%
                  \global\@nobreakfalse%
                  \clubpenalty \@M%
                  \if@afterindent%
                   \else%
                      {\setbox\z@\lastbox}%
                  \fi%
               \else%
                  \clubpenalty \@clubpenalty%
                  \everypar{}%
              \fi}}%
%
\def\@hangfrom#1{%
    \setbox\@tempboxa\hbox{{#1}}%
    \hangindent \wd\@tempboxa%
    \noindent\box\@tempboxa}%
%
%
\newcount\c@secnumdepth%
\newcount\c@tocdepth%
%
\def\secdef#1#2{\@ifstar{#2}{\@dblarg{#1}}}%
%
\def\sectionmark#1{}%
\def\subsectionmark#1{}%
\def\subsubsectionmark#1{}%
\def\paragraphmark#1{}%
\def\subparagraphmark#1{}%