Номер телефона не отображается с буквенным классом

Question

Я пишу официальное письмо, используя класс Letter. Добавляю команду \telephone{}ниже \address{}в найденный примерздесь, номер телефона не добавляется.

\documentclass{letter}
\usepackage{hyperref}
\signature{Joe Bloggs}
\address{21 Bridge Street \\ Smallville \\ Dunwich DU3 4WE}
\telephone{123456789}
\begin{document}
    
    \begin{letter}{Director \\ Doe \& Co \\ 35 Anthony Road
            \\ Newport \\ Ipswich IP3 5RT}
        \opening{Dear Sir or Madam:}
        
        I am writing to you on behalf of the Wikipedia project (http://www.wikipedia.org/),
        an endeavour to build a fully-fledged multilingual encyclopaedia in an entirely
        open manner, to ask for permission to use your copyrighted material.
        
        % The \ldots command produces dots in a way that will not upset
        % the typesetting of the document.
        \ldots 
        
        That said, allow me to reiterate that your material will be used to the noble end of
        providing a free collection of knowledge for everyone; naturally enough, only if you
        agree. If that is the case, could you kindly fill in the attached form and post it
        back to me? We shall greatly appreciate it.
        
        Thank you for your time and consideration.
        
        I look forward to your reply.
        
        \closing{Yours Faithfully,}
        
        \ps
        
        P.S. You can find the full text of GFDL license at
        \url{http://www.gnu.org/copyleft/fdl.html}.
        
        \encl{Copyright permission form}
        
    \end{letter}
\end{document}

Почему не отображается номер телефона? И еще вопрос, можно ли добавить еще и адрес электронной почты?

Answer 1

В документации к письму говорится о макросе телефона:

На всякий случай, если какой-нибудь стиль поместит это в письмо.

Чтобы добавить его, вы можете, например, переопределить \opening:

\documentclass{letter}
\usepackage{hyperref}
\signature{Joe Bloggs}
\address{21 Bridge Street \\ Smallville \\ Dunwich DU3 4WE}
\telephone{123456789}

\makeatletter
\renewcommand*\opening[1]{\ifx\@empty\fromaddress
  \thispagestyle{firstpage}%
    {\raggedleft\@date\par}%
  \else  % home address
    \thispagestyle{empty}%
    {\raggedleft\begin{tabular}{l@{}}\ignorespaces
      \fromaddress\\
      Phone~\telephonenum\\*[2\parskip]%
      \@date \end{tabular}\par}%
  \fi
  \vspace{2\parskip}%
  {\raggedright \toname \expandafter\\\toaddress \par}%
  \vspace{2\parskip}%
  #1\par\nobreak}
\makeatother


\begin{document}


    
    \begin{letter}{Director \\ Doe \& Co \\ 35 Anthony Road
            \\ Newport \\ Ipswich IP3 5RT}
        \opening{Dear Sir or Madam:}    
        I am writing to you on behalf of the Wikipedia project (http://www.wikipedia.org/),
        an endeavour to build a fully-fledged multilingual encyclopaedia in an entirely
        open manner, to ask for permission to use your copyrighted material.
        
        % The \ldots command produces dots in a way that will not upset
        % the typesetting of the document.
        \ldots 
        
        That said, allow me to reiterate that your material will be used to the noble end of
        providing a free collection of knowledge for everyone; naturally enough, only if you
        agree. If that is the case, could you kindly fill in the attached form and post it
        back to me? We shall greatly appreciate it.
        
        Thank you for your time and consideration.
        
        I look forward to your reply.
        
        \closing{Yours Faithfully,}
        
        \ps
        
        P.S. You can find the full text of GFDL license at
        \url{http://www.gnu.org/copyleft/fdl.html}.
        
        \encl{Copyright permission form}
        
    \end{letter}
\end{document}