path: root/Master/texmf-dist/tex/latex/cite/chapterbib.sty

% chapterbib.sty   Version 1.14 (31-Mar-2009) Donald Arseneau
%
% Allow multiple bibliographies in a LaTeX document, including items
% \cite'd in more than one bibliography.
%
%     Copyright (C) 1989-2009 by Donald Arseneau and Niel Kempson
%     These macros may be freely transmitted, reproduced, or modified
%     provided that this notice is left intact.
%
% Instructions are below, after \endinput.
%
%====================== BEGIN MACROS ===========================

\newenvironment{cbunit}%
{\global\advance\c@inputfile\@ne \xdef\the@ipfilectr{@-\the\c@inputfile}%
 \@namedef{b@*\@extra@b@citeb}{}%
 \@CB@writeContext}%
{\gdef\the@ipfilectr{}\@CB@writeContext}

\def\@CB@writeContext{\if@filesw\begingroup
  \edef\@tempa{\string\gdef\string\@extra@binfo{\@extra@b@citeb}}%
  \immediate\write\@auxout{\@tempa\@CB@wtoc{toc}\@CB@wtoc{lof}\@CB@wtoc{lot}}%
  \endgroup\fi}
\def\@CB@wtoc#1{\string\@writefile{#1}{\gdef
  \string\the@ipfilectr{\@extra@b@citeb}}}%

\let\cb@include\include
\def\include#1{\clearpage \cbunit \xdef\@currentipfile{#1}%
  \cb@include{#1}\global\let\@currentipfile\@savedjobname\endcbunit}

\newcommand\cb@input[1]{\cbunit \xdef\@currentipfile{#1}%
  \input{#1}\global\let\@currentipfile\@savedjobname\endcbunit}
\let\cbinput\cb@input

\@ifundefined{@extra@binfo}{% if not defined by compatible package
%  \@ifundefined{@safe@activestrue}{}{% babel is loaded
    \@ifundefined{org@bibcite}{%
      \let\bibcite@iii\bibcite
      \def\bibcite#1{\bibcite@iii{#1\@extra@binfo}}%
    }{% and will clobber us
      \let\bibcite@iii\org@bibcite
      \def\org@bibcite#1{\bibcite@iii{#1\@extra@binfo}}%
    }%}
 }{}%

\@ifundefined{@extra@b@citeb}{% if not defined by compatible package
 \def\@citex[#1]#2{%  Add \@extra@b@citeb to \cite
   \leavevmode \let\@citea\@empty
   \@cite{\@for\@citeb:=#2\do
     {\@citea\let\@citea\citepunct
      \edef\@citeb{\expandafter\@firstofone\@citeb\@empty}%
      \if@filesw\immediate\write\@auxout{\string\citation{\@citeb}}\fi
      \@ifundefined{b@\@citeb \@extra@b@citeb}{\hbox{\reset@font\bfseries ?}%
         \G@refundefinedtrue
         \@latex@warning{Citation `\@citeb' in file `\@currentipfile'
             on page \thepage \space undefined}}%
       {\@cite@ofmt{\citeform{\csname b@\@citeb 
             \@extra@b@citeb\endcsname}}}}}{#1}}
}{}%

% Test if \@extra@b@citeb hook needs to be added to \nocite
\setbox\@tempboxa\hbox{\let\@onlypreamble\document%
  \def\@extra@b@citeb{\global\let\@gtempa\relax}\@extra@b@citeb
  \def\@ifundefined#1#2#3{\global\let\@gtempa\@empty #1}%
  \@fileswfalse \nocite{x}}

\ifx\@gtempa\@empty % define \nocite with hook
\def\nocite#1{\@bsphack % Add \@extra@b@citeb to \nocite
 \ifx\@onlypreamble\document
   \@for\@citeb:=#1\do{%
     \edef\@citeb{\expandafter\@firstofone\@citeb\@empty}%
     \if@filesw\immediate\write\@auxout{\string\citation{\@citeb}}\fi
     \@ifundefined{b@\@citeb\@extra@b@citeb}{\G@refundefinedtrue
         \@warning{Citation `\@citeb' in file `\@currentipfile' undefined}}{}}%
 \else
   \@latex@error{Cannot be used in preamble}\@eha
 \fi
 \@esphack}
\fi

\@ifundefined{@cite@ofmt}{\let\@cite@ofmt\hbox}{}
\@ifundefined{citeform}{\let\citeform\@empty}{}
\@ifundefined{citepunct}{\def\citepunct{,\penalty\@m\ }}{}

\xdef\@savedjobname{\jobname}% save root file name as a macro
\let\@currentipfile\@savedjobname
\gdef\the@ipfilectr{}
\def\@extra@b@citeb{\the@ipfilectr}
\newcount\c@inputfile \global\c@inputfile=0

\gdef\@extra@binfo{}  % in case .aux files are left from old run.

\let\cb@bibliographystyle\bibliographystyle
\def\bibliographystyle#1{\if\cb@roottest\cb@bibliographystyle{#1}\fi}
\def\cb@roottest{11}%  for [rootbib]: {2\ifx\the@ipfilectr\@empty 1\else2\fi}

\def\bibliography#1{\if\cb@roottest
   \if@filesw\immediate\write\@auxout{\string\bibdata{#1}}\fi
   \fi 
   \begingroup % localize hooks into \@bibitem
   \ifx\@CitationPrefix\@empty\else \ifx\the@ipfilectr\@empty\else
     \@cb@insertprefix
   \fi\fi
   \cb@dobiblio{\@currentipfile.bbl}%
   \endgroup}

\long\def\@firstofone#1{#1}
\@ifundefined{reset@font}{\let\reset@font\relax}{}
\@ifundefined{bfseries}{\def\bfseries{\bf}}{}
\@ifundefined{G@refundefinedtrue}{\let\G@refundefinedtrue\relax}{}
\@ifundefined{PackageWarning}{\let\cb@warning\@warning}%
         {\def\cb@warning{\PackageWarning{chapterbib}}}

\@ifundefined{@newl@bel}{% pre-1995; must redefine \@testdef
   \let\@test@defiii\@testdef
   \def\@testdef#1#2#3{%
      \if#1b\relax\@test@defiii b{#2\@extra@binfo}{#3}%
      \else \@test@defiii #1{#2}{#3}\fi}%
   \let\cb@dobiblio\@input}%
  {\let\cb@dobiblio\@input@}

\def\FinalBibPrefix{\bibname\space for\space}%
\def\@auto@bibname{Bibliography}

\def\sectionbib#1#2{% Macro to convert \thebibliography command
 \@ifundefined{bibsection}{%  Regular -- patch \thebibliography
  \long\def\@tempa##1##{% to parse beginning of old def
   \long\def\@tempa####1\endthebibliography{}\def\@tempc{##1}\@tempa}%
  \expandafter\@tempa\thebibliography{}{}\endthebibliography
  \def\@tempa{\chapter*}\ifx\@tempa\@tempc\else \begingroup\toks@{#1}%
   \cb@warning {The sectionbib option changes \string"\expandafter
    \strip@prefix\meaning\@tempc\string" to \string"\the\toks@\string"
    in \string\thebibliography }\endgroup\fi
  \let\cb@thebibliography\thebibliography
  \def\thebibliography{\let\@currentlabel\@empty
    \ifx\the@ipfilectr\@empty \else
    \expandafter\expandafter\expandafter\cb@sectionbib\fi
    \cb@thebibliography}%
  \expandafter\def\expandafter\cb@sectionbib\@tempc##1{#1{\bibname}%
   \ifx\@currentlabel\@empty \begingroup \c@secnumdepth\m@ne
    \addcontentsline{toc}{#2}{\bibname}% local: * -> no num
    \csname#2mark\endcsname{\bibname}\endgroup\fi 
   \@ifnextchar\@mkboth{\@gobblethree}{}}%
 }{%  Some package or class has \bibsection -- patch that.
  \long\def\@tempa##1##{% to parse beginning of old def
   \long\def\@tempa####1\endthebibliography{}\def\@tempc{##1}\@tempa}%
  \expandafter\@tempa\bibsection{}{}\endthebibliography
  \def\@tempa{\chapter*}\ifx\@tempa\@tempc\else \begingroup\toks@{#1}%
   \cb@warning {The sectionbib option changes \string"\expandafter
    \strip@prefix\meaning\@tempc\string" to \string"\the\toks@\string"
    in \string\bibsection }\endgroup\fi
  \let\cb@bibsection\bibsection
  \def\bibsection{\let\@currentlabel\@empty
    \ifx\the@ipfilectr\@empty \else
    \expandafter\expandafter\expandafter\cb@sectionbib\fi
    \cb@bibsection}%
  \expandafter\def\expandafter\cb@sectionbib\@tempc{#1}%
}}

\long\def\@gobblethree#1#2#3{}%
\def\strip@prefix#1>{}
\@ifundefined{bibname}{\def\bibname{Bibliography}}{}

%  The following very messy hacking is to apply a prefix to each
%  cite value, shown in the cites and the bibitems, and active
%  with hyperref.  The user should declare something like:
%    \CitationPrefix{\thechapter.}
%
\let\@cb@use@prefix\@empty
\let\@CitationPrefix\@empty
%
\newcommand\bibitemPrefix[1]{%
 \def\@CitationPrefix{#1}%
 \@ifundefined{cb@emptytoks}{\newtoks\cb@emptytoks}{}%
 \cb@emptytoks={}%
 \def\@cb@valuehack##1{% hook into  "\the\value\@listctr"
   \ifx\@listctr##1% only affect "\value\@listctr"
    \cb@emptytoks % use up the preceding \the
    \@CitationPrefix % insert the prefix text
    \the % restore \the
   \fi
   \csname c@\@listctr\endcsname}% regular \value
%
% This is performed once, at the first \bibitem of each (sub-)bibliography
 \def\@cb@use@prefix{%
  \let\value\@cb@valuehack
  \def\@itemlabel{\@biblabel {\the\value\@listctr}}%
  \let\@cb@use@prefix\@empty}
}

% redefine \@lbibitem to use prefixed number; set hook to use prefix 
% (through \value) in \@bibitem also.
\def\@cb@insertprefix{% 
  \let\@cborg@lbibitem\@lbibitem \let\@cborg@bibitem\@bibitem
  \def\@bibitem{\@cb@use@prefix\@cborg@bibitem}%
  \def\@lbibitem[##1]{\@cb@use@prefix\@cborg@lbibitem[\@CitationPrefix##1]}%
}

\@ifundefined{DeclareOption}{% LaTeX2.09
  \def\@CB@wtoc#1{}% disable; broken in 2.09
}{% LaTeX2e option
\ProvidesPackage{chapterbib}[2009/03/31 \space v 1.14]
\DeclareOption{sectionbib}{\AtBeginDocument{\sectionbib{\section*}{section}}%
 \let\FinalBibPrefix\@empty
 \providecommand\StartFinalBibs{\chapter*{\bibname}%
   \begingroup \c@secnumdepth\m@ne
    \addcontentsline{toc}{chapter}{\bibname}%
    \chaptermark{\bibname}\endgroup
   \def\bibname{\@auto@bibname}}}%
\DeclareOption{draft}{\let\cbinput=\include}
\DeclareOption{rootbib}{\def\cb@roottest{2\ifx\the@ipfilectr\@empty2\else1\fi}}
\DeclareOption{duplicate}{\gdef\cb@biblist{}\let\cb@sub@input\@input@}
\DeclareOption{gather}{\gdef\cb@biblist{}\let\cb@sub@input\@gobble}
\ProcessOptions

\@ifundefined{chapter}{%
 \@ifundefined{section}{}{\providecommand\CBMainSectioning{section}}%
}{\providecommand\CBMainSectioning{chapter}}

\ifx\cb@sub@input\@input@ % For [duplicate]
 \def\cb@dofinalbibs{\if@filesw
 \toks@{\let\cb@bc\bibcite\let\bibcite\@gobbletwo}%
 \immediate\write\@auxout{\the\toks@}\fi
 \let\cb@elt\cb@dogatherbib \cb@biblist
 \if@filesw\immediate\write\@auxout{\let\string\bibcite\string\cb@bc}\fi}%
\fi

\ifx\cb@sub@input\@gobble % For [gather]
 \def\cb@dofinalbibs{\let\cb@elt\cb@dogatherbib \cb@biblist}%
\fi

\ifx\cb@biblist\@empty % duplicate or gather declared
 \providecommand\StartFinalBibs{\def\bibname{\@auto@bibname}}%
 \def\cb@dobiblio#1{\begingroup\makeatletter
  \ifx\the@ipfilectr\@empty % in root
    \StartFinalBibs \cb@dofinalbibs
  \else % in chapter, or section
    \let\cb@elt\relax % list \cb@elt{title}{input#}{file}
    \let\@ifchapapp\@secondoftwo % provide a *possible* title
    \expandafter\ifx\csname the\CBMainSectioning\endcsname\thechapter
      \@ifundefined{@chapapp}{}{\let\@ifchapapp\@firstoftwo}\fi
    \@ifundefined{FinalBibTitles}{\def\FinalBibTitles % locally
        {\FinalBibPrefix
        \@ifchapapp{\@chapapp}{\csname the\CBMainSectioning\endcsname}\space
        \csname the\CBMainSectioning\endcsname}}{}%
    \protected@xdef\cb@biblist{\cb@biblist
       \cb@elt{\FinalBibTitles}{\the\c@inputfile}{\@currentipfile}}%
    \cb@sub@input{#1}%
  \fi\endgroup}
 \def\cb@dogatherbib#1#2#3{% Title, count, fname
  \protected@edef\@auto@bibname{#1}%
  \global\c@inputfile#2\global\advance\c@inputfile\m@ne
  \IfFileExists{#3.bbl}{\cb@input{#3.bbl}}{}}
\fi

\AtBeginDocument{\let\sectionbib\undefined}
}
\endinput

%====================== BEGIN INSTRUCTIONS ===========================


 chapterbib.sty   Version 
 ~~~~~~~~~~~~~~   1.14 (31-MAR-2009) DA (\nocite*, \CitationPrefix, etc)
                  1.13 (11-DEC-2007) DA (new final-bib titling)
                  1.12 (21-MAR-2004) DA 
                  1.11 (29-FEB-2004) DA (allow \nocite check)
                  1.10 (23-JUN-2003) DA (\bibsection \CBMainSectioning)
                  1.9  (19-SEP-2001) DA (sectionbib change; babel)
                  1.8  (29-APR-1999) DA (gather, duplicate, toc)
                  1.7  (21-JUL-1997) DA (sectionbib, \nocite)
                  1.6  (08-FEB-1997) Donald Arseneau (more sectionbib)
                  1.5  (09-OCT-1995) Donald Arseneau (rootbib)
                  1.4  (11-MAR-1995) Donald Arseneau (sectionbib)
                  1.3  (04-JUL-1994) Donald Arseneau (2e, cbunit)
                  1.2  (21-MAY-1993) Donald Arseneau (bug fix)
                  1.1  (24-MAR-1993) Donald Arseneau
                  1.0  (23-NOV-1988) Niel Kempson

 Allow multiple bibliographies in a LaTeX document, including items
 \cite'd in more than one bibliography.  Despite the name "chapterbib",
 the BIBLIOGRAPHIES ARE FOR EACH INCLUDED FILE, not necessarily for each
 chapter.  The main point is to allow you to use BibTeX: Each included
 file should have its own \bibliographystyle and \bibliography commands,
 and you should run BibTeX on each included file separately rather than
 on the root file.

 There are also the commands \begin{cbunit}, \end{cbunit}, and \cbinput
 to allow multiple bibliographies without using \include (see item 4).
 There are two added hooks, \citeform and \citepunct, which you can 
 redefine to customise the formatting of each entry in a citation list,
 and the declaration \CitationPrefix to use in preference to \citeform.

 Usage, Restrictions, and Options
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 1. Normal use: Put \bibliographystyle and \bibliography commands in
    each \include'd file. Run LaTeX; run BibTeX on each included file;
    run LaTeX; run LaTeX.

 2. The \bibliography and \bibliographystyle commands are not normally used
    in the root file, only in files that have been \include'd. To have a
    whole-document bibliography, see items 6-9, depending on which style of
    whole-document bib.

 3. If you can't use \include because a new section must start below the
    preceding bibliography on the same page (odd format!), then you can
    use \begin{cbunit}...\end{cbunit} or \cbinput, with a {thebibliography}
    environment in each unit or input file.  To use BibTeX: input separate
    files using \cbinput; at first use the package or global option [draft],
    run LaTeX on the document, then BibTeX on each file that was \cbinput;
    finally, remove the [draft] option and run LaTeX again (maybe twice to
    get page references right).  The [draft] option only affects the treatment
    of \cbinput, not \include or \begin{cbunit}.
        With old LaTeX, do the preliminary run using \include commands, and
    change these to \cbinput for the final run(s).

 4. Your preferred citation style (xxx.sty) may not work with chapterbib at
    first, but it is easy to make it compatible:  In `xxx.sty' change every
    "@\@citeb" to "@\@citeb\@extra@b@citeb", and insert the line
        \@ifundefined{@extra@b@citeb}{\def\@extra@b@citeb{}}{}
    somewhere (but not as a comment or as part of another definition!).
    If the package also redefines \bibcite then you should change that
    definition, replacing "@#1" with "@#1\@extra@binfo", and insert
        \gdef\@extra@binfo{}
    somewhere in the file.
    Some citation packages deviate quite far from LaTeX's own method of
    organizing cite tags using "b@\@citeb".  The instructions above catch 
    such extensions as "Y@\@citeb", but not more radical differences.
    In such cases, try contacting the author of the citation package.
    If a citation style does not define "\nocite", then that command
    would not be converted when you make the patches to "@\@citeb".
    Chapterbib will try to detect the hook in "\nocite", but if this fails
    you may need to redefine "\nocite" (with any "@\@citeb" changed to 
    "@\@citeb\@extra@b@citeb") in that sty file.

 5. The report and book document classes usually treat the bibliography as
    an unnumbered chapter (\chapter*), which is not so good for bibliographies
    IN a chapter.  You can specify
        \usepackage[sectionbib]{chapterbib}
    to convert your bibliographies from \chapter* to \section*, with an
    entry in the table of contents and the page-header.  A bibliography in
    the root file remains as a \chapter*.  The [sectionbib] option modifies
    the existing thebibliography environment (or the \bibsection command, if
    present already), so the other formatting in the  bibliography should
    remain unchanged.  On the other hand, if you already have a non-standard
    bibliography defined, or if you want them numbered, it may be easier to
    redefine \thebibliography directly, without any trickery.
        Alternatively, you can use the \sectionbib command directly in the
    document preamble.  It takes two parameters: the sectioning command, and
    the name of the sectioning level.  For instance, the [sectionbib] option
    does \sectionbib{\section*}{section}. Again, for the most control, it is
    better to redefine \thebibliography entirely.

 6. If you want a completely unrelated bibliography in the root file, perhaps
    for a general reading list, you can provide your own bibliography there
    using the thebibliography environment.  I don't suppose this will appeal
    to BibTeX users!

 7. To have a cohesive bibliography for the whole document, plus individual
    bibs in the chapters, put \bibliography commands in the included chapters
    plus in the root file.  Make sure the \bibliographystyle for the overall
    bibliography appears FIRST, before any chapters are included. Run LaTeX;
    run BibTeX on the root file; run BibTeX on each included file; run LaTeX; 
    run LaTeX. This produces an independent `overall' bibliography which only
    makes sense for various `named' bibliography styles; a numbered style, or
    one with any type of automatic enumeration (like Me2007a, Me2007b) will 
    give unrelated numbers in each bibliography and lead to confusion.
        Bibtex will complain about multiple \bibdata commands when it makes
    the whole bibliography, but it should obey the first.  If you don't 
    want to see any error messages from bibtex, or if you don't want to put 
    the main \bibliographystyle command first in the document, then use 
    \usepackage[rootbib]{chapterbib} when you run LaTeX first; run BibTeX 
    on the root file; change to \usepackage{chapterbib}; run LaTeX; run 
    BibTeX on each included file; run LaTeX; run LaTeX.

 8. To have a bibliography-by-chapter at the end instead of separate bibs
    in the chapters, use \usepackage[gather]{chapterbib}, put \bibliography
    commands in each file, and at the end of the main file. Run LaTeX as
    in item 1. You can control the titling of the final bibliographies by
    defining \FinalBibTitles, such as

      \newcommand\FinalBibTitles{References for Chapter \thechapter}

    A similar effect may be achived by RE-defining \FinalBibPrefix as

      \renewcommand\FinalBibPrefix{References for }

    Even more control is achieved by redefining \StartFinalBibs.
    The default definition is (like)

      \newcommand{\StartFinalBibs}{%
        \renewcommand{\bibname}{Bibliography for chapter n}}

    normally, but when using the [sectionbib] option it becomes

      \newcommand{\StartFinalBibs}{\chapter*{\bibname}%
        \addcontentsline{toc}{chapter}{\bibname}\@mkboth{\bibname}{\bibname}%
        \renewcommand{\bibname}{Chapter n}}

    where the \bibname text is now provided by \@auto@bibname, which 
    relies on bookkeeping and \FinalBibPrefix. 

    If your document class has neither section nor chapter, then you must
    define \StartFinalBibs and also indicate the sectioning: for example,
    if the main sectioning command in your document class is \motif:
        \newcommand\CBMainSectioning{motif}

 9. To have bibliographies in each chapter PLUS a bibliography-by-chapter at
    the end, follow item 9, but declare \usepackage[duplicate]{chapterbib}
    (or \usepackage[duplicate,sectionbib]{chapterbib}).

10. If you use Babel, load chapterbib before babel.

 \citeform, \citepunct and \CitationPrefix:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Normally, the citations are formatted as given, but you can define \citeform
 (with one parameter) to reformat every citation.  Some possibilities:
  \renewcommand\citeform[1]{\romannumeral 0#1}% roman numerals:  [iv,x]
  \renewcommand\citeform[1]{(#1)}             % parentheses:  [(3),(4),(7)]
 If you change \citeform, you should probably define \@biblabel to match.

 Another not-so-good example to provide a chapter-number prefix is
  \renewcommand\citeform[1]{\thechapter.#1}   % number by chapter.
 This partially works, but has only limited applicability: it does not 
 work with cites in the front-matter (TOC, LOF) or with hyperref.
 Instead, there is a \CitationPrefix command to apply a prefix to the 
 citation numbers (or names) in the bibliographies and \cite commands 
 for the included files. Use it by declaring something like
  \CitationPrefix{\thechapter.}
 in the preamble.  The prefix will be applied to all the chapter-bibs
 but will not be used in an overall (root) bibliography, if you have one.
 
 \citepunct gives the punctuation (comma-penalty-space) between items
 in the \cite list.

%====================== END INSTRUCTIONS ===========================
%
% -----------------Implementation notes---------------
%
% LaTeX normally uses command names in the form \b@TAG to associate a mnemonic
% TAG with the citation name or number.  Chapterbib changes this to a command
% like \b@TAG@-nn where nn is a number identifying which included file is in
% effect.
%
% Tags indicating the citations and/or the input files:
% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
% \c@inputfile    = counter counting included files
% \the@ipfilectr  = (empty) when typesetting from the root file,
%                 = @-\the\c@inputfile when typesetting from an included file
% \@extra@b@citeb = \the@ipfilectr (just an alias)
% \@extra@binfo   = the value of \@extra@b@citeb as saved in .aux files
%
% \b@FOO:
% ~~~~~~~
% In the root file, the citation number (or name) is given by \b@FOO
% just like regular LaTeX, but in an \include'd file it is given by
% \b@FOO@-number.  Any definition of \cite (\@citex) should refer
% to this using \csname b@\@citeb\@extra@b@citeb \endcsname.
%
% \include \cbinput and \cbunit:
% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
% Redefine the \include macro so that when a file is \include'd...
% Increment the file number, (globally) update \the@ipfilectr to be
% @-number, and write \gdef\@extra@binfo{@-number} in the (main) .aux
% file, and do regular \include. When the \include'd file is finished,
% write \gdef\@extra@binfo{} in the (main) .aux file. Globally reset
% \the@ipfilectr to {}.  Provide similar \cbunit and \cbinput.
%
% \cite:
% ~~~~~~
% Redefine \cite (\@citex actually) and \bibcite to use the file number
% tag along with the specified tag.  \@citex also uses \citeform as a hook
% to reformat each individual citation.
% Only do the redefinitions if no citation style that supports chapterbib
% has been loaded--as indicated by existence of filename tags.
%
% \nocite:
% ~~~~~~~~
% A while ago LaTeX changed its \nocite so it checks the validity of the
% (no)citation tags.  This necessitated adding the "\@extra@b@citeb" hook
% to \nocite.  At first, I only redefined \nocite when redefining \cite,
% but there existed citation packages that supported chapterbib by putting
% \@extra@b@citeb into \cite but which did not define \nocite at all!
% These then gave warning messages for every \nocite.  With version 1.7,
% I now try exercising the \nocite command with some functions disabled:
% (1) .aux file output is locally switched off; (2) The \@ifundefined
% command is hacked to merely typeset the text of the tag; (3) this is
% done in a disappearing \hbox so it generates no output.  This detects
% (by setting a global flag \@gtempa) a \nocite command that executes
% \@ifundefined but not \@extra@b@citeb.  In such cases, \nocite must
% be redefined.
%
% \citepunct and \citeform:
% ~~~~~~~~~~~~~~~~~~~~~~~~~
% These customization hooks are present in cite.sty; others (\citemid,
% \citeleft, \citeright) are not defined here because \@cite is not redefined.
% LaTeX has now adopted \@cite@ofmt, which is normally \hbox, so use both.
%
% We redefine \@testdef so that it properly checks whether the
% \cite labels have changed.
%
% Table of contents etc:
% ~~~~~~~~~~~~~~~~~~~~~~
% As of version 1.8, definitions of \@extra@b@citeb are written to the
% toc, lot, and lof files to avoid undefined citation tags in those tables.
% This is actually a problem in regular LaTeX with bibTeX -- cites that
% appear in those tables get numbered starting with 1, but they should
% be sequenced by where they originated -- but the problem was worse with
% chapterbib.
%
% \CitationPrefix:
% ~~~~~~~~~~~~~~~~
% This is a really ugly hack, but \citeform worked poorly for putting
% a chapter-identifier on each cite.  It locally redefines both
% \@bibitem and \@lbibitem at each \bibliography.  The insertion
% of the prefix is straightforward for \@lbibitem, but for \@bibitem
% the prefix is inserted by a redefined \value macro (eeek!). 
%
%---------------------------------------------------------------
%
% Authors  Niel Kempson        (original)
% ~~~~~~~  Donald Arseneau  <asnd@triumf.ca>   March 1993 - Mar 2009
%
% Changes with ver 1.14: No warning from \nocite* in chapters, \CitationPrefix 
% Changes with ver 1.13: Rewrite final-bibs titling
% Changes with ver 1.12: Update \@citex \bfseries
% Changes with ver 1.11: Follow LaTeX's barring \nocite from preamble
% Changes with ver 1.10: \CBMainSectioning; \bibsection hook
% Changes with ver 1.9: sectionbib remove \@mkboth
% Changes with ver 1.8: options gather and duplicate; babel workarounds; toc
% Changes with ver 1.7: change the \sectionbib command re. headings.
%                       update \nocite and alter \citeform
% Changes with ver 1.6: change the \sectionbib command to take arguments.
% Changes with ver 1.5: rootbib option; item 8 in instructions.
% Changes with ver 1.4: sectionbib and draft options
% Changes with ver 1.3: rewrite:
% The filename tag is defined in each .aux file by \include, not as an
% extra parameter to \bibcite.  \@bibitem & \@lbibitem are left alone.  Add
% \citeform and \citepunct. Add \cbunit and \cbinput for use without \include.
%