🚀 go-pugleaf

Our site has recently installed a new version of LaTeX (under UNIX).  
But I've since found that a style file which previously worked like a 
dream now crashes with a strange error message.  

I'm not sufficiently familiar with plain TeX (in which the style file is
written), and not familiar at all with the changes made to LaTeX, to be 
able to even guess at where the problem lies and what to do about it.

Here's what happens...  Starting from scratch, I run LaTeX on my source 
file.  Everything is OK.  I run bibtex to create the bibliography.  
Everything is still OK.  I run LaTeX a second time.  Fine.  I run LaTeX
a third time to get the cross-references right.  It is here that LaTeX
finally crashes with the following error:

  % latex hopf
  This is TeX, C Version 3.14t3
  (hopf.tex
  LaTeX Version 2.09 <18 March 1992>
  (/usr/local/lib/tex/inputs/article.sty
  Standard Document Style `article' <14 Jan 92>.
  
    [ reads in style files ]
  
    [ reads in .aux files ]
  
  [1] [2] (sec1.tex
  ! Argument of \@incite has an extra }.
  <inserted text> 
                  \par 
  <to be read again> 
                     }
  l.4 ...ogical solitons [\incite{belavinpolyakov75}
                                                    ; for a review,
  ? x
  Output written on hopf.dvi (2 pages, 2112 bytes).
  Transcript written on hopf.log.

The \incite macro (which produces citations of the form "Smith (1990)") is
defined in the natsci.sty style file and the relevant code is given below:

  % natsci.sty  28 Feb 91
  % You also need the file natsci.bst to get the most out of this.
  % Use with LaTeX version 2.09 article document style
  % and the natsci bibliography style:
  % \documentstyle[natsci]{article}
  % \begin{document}
  % \bibliographystyle{natsci}
  % Copyright (c) 1987 by Stephen Gildea
  % 1987 original version
  % 22 Feb 89 small changes
  % 27 Feb 91 added \incite
  
  [ stuff deleted ]
  
  % \incite puts the parens only around the date, not the entire citation,
  % for when the work is referenced in running text.
  
  \def\incite#1{{\let\@citex\@incitex\cite{#1}}}
  
  \def\@incitex[#1]#2{\if@filesw\immediate\write\@auxout{\string\citation{#2}}
     \fi
     \@ifundefined{b@#2}%
        {{\bf ?}\@warning{Citation `#2' on page \thepage \space undefined}}%
        {\edef\@citeb{\csname b@#2\endcsname}\expandafter\@incite\@citeb;}}

  % find the comma and put leading paren in place of it
  \def\@incite#1, #2;{#1 (#2)}

Does this part of natsci.sty need altering to accomodate the changes in
LaTeX?  (If so, how?)  Or does the source of the error lie elsewhere?  

Any help will be appreciated.  

Michael.

--
Michael S. Ody,
The Physics Laboratory,
University of Kent at Canterbury,
CT2 7NZ,  United Kingdom.