LaTeX 样式文件中的纸张尺寸规范

Question

我需要更改所附样式文件上的纸张大小。该文件似乎是针对欧洲 A4 纸张大小的，我需要将其更改为美国信纸大小（8.5 x 11 英寸）。此文件中的哪一行指的是纸张大小？我该如何更改它？

\def\ps@sepone{%
\def\@oddhead{}
\def\@evenhead{}
\def\@oddfoot{\hfil\it\sepfoot\hfil}
\def\@evenfoot{\hfil\it\sepfoot\hfil}}
\def\ps@sep{%
\def\@oddhead{\hbox{}\it\seprhead\hfil\it\seplhead}
\def\@evenhead{\it\seprhead\hfil\it\seplhead\hbox{}}
\def\@oddfoot{\hfil\it\sepfoot\hfil}
\def\@evenfoot{\hfil\it\sepfoot\hfil}}
\pagestyle{sep}
\def\righthead#1{\def\seplhead{#1}}
\def\lefthead#1{\def\seprhead{#1}}
\def\footer#1{\def\sepfoot{#1}}
\footer{}
\lefthead{}
\righthead{}
\thispagestyle{sepone}
\def\makefootline{\baselineskip24\p@\line{\the\footline}}
\def\makeheadline{\vbox to 0pt{\vskip-22.5pt \line{vbox to 8.5pt{}\the\headline}\vss}\nointerlineskip}

\newfont{\bigbf}{cmbx10 scaled\magstep 3}
\newfont{\bigit}{cmti10 scaled\magstep 1}
\newfont{\bigrm}{cmr10 scaled\magstep 1}

\textheight=9in
\textwidth=6.4in
\textfloatsep 30pt plus 3pt minus 6pt
\parskip=5pt
\oddsidemargin=-.2in
\voffset=-.1in
\newdimen\singlespacing
\singlespacing=11pt     % single line spacing
\normalbaselineskip=15pt     % 1.5 line spacing
\baselineskip=\normalbaselineskip

% multi-line title
\newenvironment{SEPtitle}{\begin{center}\bigbf}{\end{center}}
\def\title#1{
    \begin{SEPtitle}
    \vbox{\baselineskip=1.5\normalbaselineskip
    \vskip1in #1\vskip.3in}
    \end{SEPtitle}}
% multi-line author
\newenvironment{SEPauthor}{\begin{center}\bigit}{\end{center}}
\def\author#1{
    \begin{SEPauthor}
    \vbox{#1 \vskip.3cm}
    \end{SEPauthor}}
\newenvironment{SEPauthoraff}{\begin{center}\bigrm}{\end{center}}
\def\authoraff#1{
    \begin{SEPauthoraff}
    \vbox{#1 \vskip.2in}
    \end{SEPauthoraff}}
% multi-line centered section heading
\newenvironment{SEPmhead}{\begin{center}\bf}{\end{center}}
\def\mhead#1{\pagebreak[3]
    \begin{SEPmhead}\pagebreak[3]
    \vbox{\vskip.3in #1}\nopagebreak
    \end{SEPmhead}\nopagebreak}
% multi-line left-justified subheading
\newenvironment{SEPshead}{\begin{flushleft}\bf}{\end{flushleft}}
\def\shead#1{\pagebreak[3]
    \begin{SEPshead}\pagebreak[3]
    \vbox{\vskip.2in #1}\nopagebreak
    \end{SEPshead}\nopagebreak}

% define ABSTRACT, INTRODUCTION, DISCUSSION, CONCLUSIONS, REFERENCES,
% and APPENDIX as the first three letters
\def\ABS{\mhead{ABSTRACT}}
\def\INT{\mhead{INTRODUCTION}}
\def\DIS{\mhead{DISCUSSION}}
\def\CON{\mhead{CONCLUSIONS}}
\def\ACK{\mhead{ACKNOWLEDGMENT}}
\def\REF{\mhead{REFERENCES}}
\def\APP{\mhead{APPENDIX}}

% reference macro, second ... lines are indented
\newdimen\dtmp     % temporary dimension variable
\def\reference#1{ \baselineskip=\singlespacing \dtmp=\hsize
        \advance\dtmp by-\parindent \parshape 2 0in \hsize \parindent
        \dtmp \noindent #1 \endgraf \baselineskip=\normalbaselineskip
        \vskip4pt
        }

\newcommand{\bs}{$\backslash$}
\def\under{\underline}
\def\dotdot{\ddot}
\def\nwl{\hfill\break}      % similar to latex's \newline but does not
                % complain if there is no line to break
\def\ind#1{\par\everypar{\hangindent=#1\hangafter=0\hskip-\parindent}}
\def\tmpind#1{\par\hskip#1}
\newenvironment{SEPcntr}{\begin{center}}{\end{center}}
\def\cntr#1{\begin{SEPcntr} #1 \end{SEPcntr}}
% displayed text, indented, justification off
\def\displaybegin{\par\begingroup\medskip\narrower\narrower\noindent
          \obeylines\obeyspaces}
\def\displayend{\endgroup\smallskip\noindent}
% fill and nofill
\def\nofill{\par\begingroup\noindent\obeylines\obeyspaces}
\def\fill{\endgroup\noindent}

% define a boxing macro
\def\boxit#1{\vbox{\hrule\hbox{\vrule\kern10pt\vbox{\medskip\kern5pt#1\bigskip
\kern5pt}\kern10pt\vrule}\hrule}}