%% 

 %% Copyright 2007, 2008, 2009 Elsevier Ltd

 %% 

 %% This file is part of the 'Elsarticle Bundle'.

 %% ---------------------------------------------

 %% 

 %% It may be distributed under the conditions of the LaTeX Project Public

 %% License, either version 1.2 of this license or (at your option) any

 %% later version.  The latest version of this license is in

 %%    http://www.latex-project.org/lppl.txt

 %% and version 1.2 or later is part of all distributions of LaTeX

 %% version 1999/12/01 or later.

 %% 

 %% The list of all files belonging to the 'Elsarticle Bundle' is

 %% given in the file `manifest.txt'.

 %% 

  %%-------------------------------------------------------------------

  %% This bibliography style file is intended for texts in ENGLISH

  %% This is an author-year citation style bibliography. As such, it is

  %% non-standard LaTeX, and requires a special package file

  %% to function properly.

  %% Such a package is    natbib.sty   by Patrick W. Daly

  %% The form of the \bibitem entries is

  %%   \bibitem[Jones et al.(1990)]{key}...

  %%   \bibitem[Jones et al.(1990)Jones, Baker, and Smith]{key}...

  %% The essential feature is that the label (the part in brackets) consists

  %% of the author names, as they should appear in the citation, with the year

  %% in parentheses following. There must be no space before the opening

  %% parenthesis!

  %% With natbib v5.3, a full list of authors may also follow the year.

  %% In natbib.sty, it is possible to define the type of enclosures that is

  %% really wanted (brackets or parentheses), but in either case, there must

  %% be parentheses in the label.

  %% The \cite command functions as follows:

  %%   \citet{key} ==>>                Jones et al. (1990)

  %%   \citet*{key} ==>>               Jones, Baker, and Smith (1990)

  %%   \citep{key} ==>>                (Jones et al., 1990)

  %%   \citep*{key} ==>>               (Jones, Baker, and Smith, 1990)

  %%   \citep[chap. 2]{key} ==>>       (Jones et al., 1990, chap. 2)

  %%   \citep[e.g.][]{key} ==>>        (e.g. Jones et al., 1990)

  %%   \citep[e.g.][p. 32]{key} ==>>   (e.g. Jones et al., p. 32)

  %%   \citeauthor{key} ==>>           Jones et al.

  %%   \citeauthor*{key} ==>>          Jones, Baker, and Smith

  %%   \citeyear{key} ==>>             1990

  %%---------------------------------------------------------------------

 ENTRY

   { address

     author

     booktitle

     chapter

     edition

     editor

     howpublished

     institution

     journal

     key

     month

     note

     number

     organization

     pages

     publisher

     school

     series

     title

     type

     url

     volume

     year

   }

   {}

   { label extra.label sort.label short.list }

 INTEGERS { output.state before.all mid.sentence after.sentence after.block }

 FUNCTION {init.state.consts}

 { #0 'before.all :=

   #1 'mid.sentence :=

   #2 'after.sentence :=

   #3 'after.block :=

 }

 STRINGS { s t }

 FUNCTION {output.nonnull}

 { 's :=

   output.state mid.sentence =

     { ", " * write$ }

     { output.state after.block =

         { add.period$ write$

           newline$

           "\newblock " write$

         }

         { output.state before.all =

             'write$

             { add.period$ " " * write$ }

           if$

         }

       if$

       mid.sentence 'output.state :=

     }

   if$

   s

 }

 FUNCTION {output}

 { duplicate$ empty$

     'pop$

     'output.nonnull

   if$

 }

 FUNCTION {output.check}

 { 't :=

   duplicate$ empty$

     { pop$ "empty " t * " in " * cite$ * warning$ }

     'output.nonnull

   if$

 }

 FUNCTION {fin.entry}

 { add.period$

   write$

   newline$

 }

 FUNCTION {new.block}

 { output.state before.all =

     'skip$

     { after.block 'output.state := }

   if$

 }

 FUNCTION {new.sentence}

 { output.state after.block =

     'skip$

     { output.state before.all =

         'skip$

         { after.sentence 'output.state := }

       if$

     }

   if$

 }

 %%SP 2003/07/25

 %% No longer used

 FUNCTION {add.blank}

 {  " " * before.all 'output.state :=

 }

 FUNCTION {date.block}

 {

   new.sentence

 }

 FUNCTION {not}

 {   { #0 }

     { #1 }

   if$

 }

 FUNCTION {and}

 {   'skip$

     { pop$ #0 }

   if$

 }

 FUNCTION {or}

 {   { pop$ #1 }

     'skip$

   if$

 }

 FUNCTION {new.block.checkb}

 { empty$

   swap$ empty$

   and

     'skip$

     'new.block

   if$

 }

 FUNCTION {field.or.null}

 { duplicate$ empty$

     { pop$ "" }

     'skip$

   if$

 }

 FUNCTION {emphasize}

 { skip$ }

 FUNCTION {capitalize}

 { "u" change.case$ "t" change.case$ }

 FUNCTION {space.word}

 { " " swap$ * " " * }

  %% Here are the language-specific definitions for explicit words.

  %% Each function has a name bbl.xxx where xxx is the English word.

  %% The language selected here is ENGLISH

 FUNCTION {bbl.and}

 { "and"}

 FUNCTION {bbl.etal}

 { "et~al." }

 FUNCTION {bbl.editors}

 { "Eds." }

 FUNCTION {bbl.editor}

 { "Ed." }

 FUNCTION {bbl.edby}

 { "edited by" }

 FUNCTION {bbl.edition}

 { "Edition" }

 FUNCTION {bbl.volume}

 { "Vol." }

 FUNCTION {bbl.of}

 { "of" }

 FUNCTION {bbl.number}

 { "no." }

 FUNCTION {bbl.nr}

 { "no." }

 FUNCTION {bbl.in}

 { "in" }

 FUNCTION {bbl.pages}

 { "pp." }

 FUNCTION {bbl.page}

 { "p." }

 FUNCTION {bbl.chapter}

 { "Ch." }

 FUNCTION {bbl.techrep}

 { "Tech. Rep." }

 FUNCTION {bbl.mthesis}

 { "Master's thesis" }

 FUNCTION {bbl.phdthesis}

 { "Ph.D. thesis" }

 FUNCTION {bbl.first}

 { "1st" }

 FUNCTION {bbl.second}

 { "2nd" }

 FUNCTION {bbl.third}

 { "3rd" }

 FUNCTION {bbl.fourth}

 { "4th" }

 FUNCTION {bbl.fifth}

 { "5th" }

 FUNCTION {bbl.st}

 { "st" }

 FUNCTION {bbl.nd}

 { "nd" }

 FUNCTION {bbl.rd}

 { "rd" }

 FUNCTION {bbl.th}

 { "th" }

 MACRO {jan} {"Jan."}

 MACRO {feb} {"Feb."}

 MACRO {mar} {"Mar."}

 MACRO {apr} {"Apr."}

 MACRO {may} {"May"}

 MACRO {jun} {"Jun."}

 MACRO {jul} {"Jul."}

 MACRO {aug} {"Aug."}

 MACRO {sep} {"Sep."}

 MACRO {oct} {"Oct."}

 MACRO {nov} {"Nov."}

 MACRO {dec} {"Dec."}

 FUNCTION {eng.ord}

 { duplicate$ "1" swap$ *

   #-2 #1 substring$ "1" =

      { bbl.th * }

      { duplicate$ #-1 #1 substring$

        duplicate$ "1" =

          { pop$ bbl.st * }

          { duplicate$ "2" =

              { pop$ bbl.nd * }

              { "3" =

                  { bbl.rd * }

                  { bbl.th * }

                if$

              }

            if$

           }

        if$

      }

    if$

 }

 MACRO {acmcs} {"ACM Comput. Surv."}

 MACRO {acta} {"Acta Inf."}

 MACRO {cacm} {"Commun. ACM"}

 MACRO {ibmjrd} {"IBM J. Res. Dev."}

 MACRO {ibmsj} {"IBM Syst.~J."}

 MACRO {ieeese} {"IEEE Trans. Softw. Eng."}

 MACRO {ieeetc} {"IEEE Trans. Comput."}

 MACRO {ieeetcad}

  {"IEEE Trans. Comput.-Aided Design Integrated Circuits"}

 MACRO {ipl} {"Inf. Process. Lett."}

 MACRO {jacm} {"J.~ACM"}

 MACRO {jcss} {"J.~Comput. Syst. Sci."}

 MACRO {scp} {"Sci. Comput. Programming"}

 MACRO {sicomp} {"SIAM J. Comput."}

 MACRO {tocs} {"ACM Trans. Comput. Syst."}

 MACRO {tods} {"ACM Trans. Database Syst."}

 MACRO {tog} {"ACM Trans. Gr."}

 MACRO {toms} {"ACM Trans. Math. Softw."}

 MACRO {toois} {"ACM Trans. Office Inf. Syst."}

 MACRO {toplas} {"ACM Trans. Prog. Lang. Syst."}

 MACRO {tcs} {"Theoretical Comput. Sci."}

 FUNCTION {write.url}

 { url empty$

     { skip$ }

     { "\newline\urlprefix\url{" url * "}" * write$ newline$ }

   if$

 }

 INTEGERS { nameptr namesleft numnames }

 FUNCTION {format.names}

 { 's :=

   #1 'nameptr :=

   s num.names$ 'numnames :=

   numnames 'namesleft :=

     { namesleft #0 > }

     { s nameptr

       "{vv~}{ll}{, jj}{, f.}" format.name$

     't :=

       nameptr #1 >

         {

           namesleft #1 >

             { ", " * t * }

             {

               "," *

               s nameptr "{ll}" format.name$ duplicate$ "others" =

                 { 't := }

                 { pop$ }

               if$

               t "others" =

                 {

                   " " * bbl.etal *

                 }

                 { " " * t * }

               if$

             }

           if$

         }

         't

       if$

       nameptr #1 + 'nameptr :=

       namesleft #1 - 'namesleft :=

     }

   while$

 }

 FUNCTION {format.names.ed}

 { format.names }

 FUNCTION {format.key}

 { empty$

     { key field.or.null }

     { "" }

   if$

 }

 FUNCTION {format.authors}

 { author empty$

     { "" }

     { author format.names }

   if$

 }

 FUNCTION {format.editors}

 { editor empty$

     { "" }

     { editor format.names

       editor num.names$ #1 >

         { " (" * bbl.editors * ")" * }

         { " (" * bbl.editor * ")" * }

       if$

     }

   if$

 }

 FUNCTION {format.in.editors}

 { editor empty$

     { "" }

     { editor format.names.ed

       editor num.names$ #1 >

         { " (" * bbl.editors * ")" * }

         { " (" * bbl.editor * ")" * }

       if$

     }

   if$

 }

 FUNCTION {format.note}

 {

  note empty$

     { "" }

     { note #1 #1 substring$

       duplicate$ "{" =

         'skip$

         { output.state mid.sentence =

           { "l" }

           { "u" }

         if$

         change.case$

         }

       if$

       note #2 global.max$ substring$ *

     }

   if$

 }

 FUNCTION {format.title}

 { title empty$

     { "" }

     { title "t" change.case$

     }

   if$

 }

 FUNCTION {format.full.names}

 {'s :=

   #1 'nameptr :=

   s num.names$ 'numnames :=

   numnames 'namesleft :=

     { namesleft #0 > }

     { s nameptr

       "{vv~}{ll}" format.name$

       't :=

       nameptr #1 >

         {

           namesleft #1 >

             { ", " * t * }

             {

               numnames #2 >

                 { "," * }

                 'skip$

               if$

               s nameptr "{ll}" format.name$ duplicate$ "others" =

                 { 't := }

                 { pop$ }

               if$

               t "others" =

                 {

                   " " * bbl.etal *

                 }

                 { bbl.and

                   space.word * t *

                 }

               if$

             }

           if$

         }

         't

       if$

       nameptr #1 + 'nameptr :=

       namesleft #1 - 'namesleft :=

     }

   while$

 }

 FUNCTION {author.editor.key.full}

 { author empty$

     { editor empty$

         { key empty$

             { cite$ #1 #3 substring$ }

             'key

           if$

         }

         { editor format.full.names }

       if$

     }

     { author format.full.names }

   if$

 }

 FUNCTION {author.key.full}

 { author empty$

     { key empty$

          { cite$ #1 #3 substring$ }

           'key

       if$

     }

     { author format.full.names }

   if$

 }

 FUNCTION {editor.key.full}

 { editor empty$

     { key empty$

          { cite$ #1 #3 substring$ }

           'key

       if$

     }

     { editor format.full.names }

   if$

 }

 FUNCTION {make.full.names}

 { type$ "book" =

   type$ "inbook" =

   or

     'author.editor.key.full

     { type$ "proceedings" =

         'editor.key.full

         'author.key.full

       if$

     }

   if$

 }

 FUNCTION {output.bibitem}

 { newline$

   "\bibitem[{" write$

   label write$

   ")" make.full.names duplicate$ short.list =

      { pop$ }

      { * }

    if$

   "}]{" * write$

   cite$ write$

   "}" write$

   newline$

   ""

   before.all 'output.state :=

 }

 FUNCTION {n.dashify}

 {

   't :=

   ""

     { t empty$ not }

     { t #1 #1 substring$ "-" =

         { t #1 #2 substring$ "--" = not

             { "--" *

               t #2 global.max$ substring$ 't :=

             }

             {   { t #1 #1 substring$ "-" = }

                 { "-" *

                   t #2 global.max$ substring$ 't :=

                 }

               while$

             }

           if$

         }

         { t #1 #1 substring$ *

           t #2 global.max$ substring$ 't :=

         }

       if$

     }

   while$

 }

 FUNCTION {word.in}

 { bbl.in capitalize

   ":" *

   " " * }

 FUNCTION {format.date}

 { year duplicate$ empty$

     { "empty year in " cite$ * "; set to ????" * warning$

        pop$ "????" }

     'skip$

   if$

   month empty$

     'skip$

     { month

       " " * swap$ *

     }

   if$

   extra.label *

   before.all 'output.state :=

   ", " swap$ *

 }

 FUNCTION {format.btitle}

 { title

 }

 FUNCTION {tie.or.space.connect}

 { duplicate$ text.length$ #3 <

     { "~" }

     { " " }

   if$

   swap$ * *

 }

 FUNCTION {either.or.check}

 { empty$

     'pop$

     { "can't use both " swap$ * " fields in " * cite$ * warning$ }

   if$

 }

 FUNCTION {format.bvolume}

 { volume empty$

     { "" }

     { bbl.volume volume tie.or.space.connect

       series empty$

         'skip$

         { bbl.of space.word * series emphasize * }

       if$

       "volume and number" number either.or.check

     }

   if$

 }

 FUNCTION {format.number.series}

 { volume empty$

     { number empty$

         { series field.or.null }

         { output.state mid.sentence =

             { bbl.number }

             { bbl.number capitalize }

           if$

           number tie.or.space.connect

           series empty$

             { "there's a number but no series in " cite$ * warning$ }

             { bbl.in space.word * series * }

           if$

         }

       if$

     }

     { "" }

   if$

 }

 FUNCTION {is.num}

 { chr.to.int$

   duplicate$ "0" chr.to.int$ < not

   swap$ "9" chr.to.int$ > not and

 }

 FUNCTION {extract.num}

 { duplicate$ 't :=

   "" 's :=

   { t empty$ not }

   { t #1 #1 substring$

     t #2 global.max$ substring$ 't :=

     duplicate$ is.num

       { s swap$ * 's := }

       { pop$ "" 't := }

     if$

   }

   while$

   s empty$

     'skip$

     { pop$ s }

   if$

 }

 FUNCTION {convert.edition}

 { edition extract.num "l" change.case$ 's :=

   s "first" = s "1" = or

     { bbl.first 't := }

     { s "second" = s "2" = or

         { bbl.second 't := }

         { s "third" = s "3" = or

             { bbl.third 't := }

             { s "fourth" = s "4" = or

                 { bbl.fourth 't := }

                 { s "fifth" = s "5" = or

                     { bbl.fifth 't := }

                     { s #1 #1 substring$ is.num

                         { s eng.ord 't := }

                         { edition 't := }

                       if$

                     }

                   if$

                 }

               if$

             }

           if$

         }

       if$

     }

   if$

   t

 }

 FUNCTION {format.edition}

 { edition empty$

     { "" }

     { output.state mid.sentence =

         { convert.edition "l" change.case$ " " * bbl.edition * }

         { convert.edition "t" change.case$ " " * bbl.edition * }

       if$

     }

   if$

 }

 INTEGERS { multiresult }

 FUNCTION {multi.page.check}

 { 't :=

   #0 'multiresult :=

     { multiresult not

       t empty$ not

       and

     }

     { t #1 #1 substring$

       duplicate$ "-" =

       swap$ duplicate$ "," =

       swap$ "+" =

       or or

         { #1 'multiresult := }

         { t #2 global.max$ substring$ 't := }

       if$

     }

   while$

   multiresult

 }

 FUNCTION {format.pages}

 { pages empty$

     { "" }

     { pages multi.page.check

         { bbl.pages pages n.dashify tie.or.space.connect }

         { bbl.page pages tie.or.space.connect }

       if$

     }

   if$

 }

 FUNCTION {format.journal.pages}

 { pages empty$

     'skip$

     { duplicate$ empty$

         { pop$ format.pages }

         {

           ", " *

           pages n.dashify *

         }

       if$

     }

   if$

 }

 %%SP 2001/01/23

 %% Only used in articles

 FUNCTION {format.vol.num.pages}

 {

 %%SP 2001/01/23

 %% Add the leading space only if there is a volume

   %% volume field.or.null

   " "

   volume empty$

     { pop$ "" }

     { volume * }

   if$

   number empty$

     'skip$

     {

       "~(" number * ")" * *

       volume empty$

         { "there's a number but no volume in " cite$ * warning$ }

         'skip$

       if$

     }

   if$

 }

 FUNCTION {format.chapter.pages}

 { chapter empty$

     { "" }

     { type empty$

         { bbl.chapter }

         { type "l" change.case$ }

       if$

       chapter tie.or.space.connect

     }

   if$

 }

 FUNCTION {format.in.ed.booktitle}

 { booktitle empty$

     { "" }

     { editor empty$

         { word.in booktitle * }

         { word.in format.in.editors * ", " *

           booktitle * }

       if$

     }

   if$

 }

 FUNCTION {format.thesis.type}

 { type empty$

     'skip$

     { pop$

       type "t" change.case$

     }

   if$

 }

 FUNCTION {format.tr.number}

 { type empty$

     { bbl.techrep }

     'type

   if$

   number empty$

     { "t" change.case$ }

     { number tie.or.space.connect }

   if$

 }

 FUNCTION {format.article.crossref}

 {

   word.in

   " \cite{" * crossref * "}" *

 }

 FUNCTION {format.book.crossref}

 { volume empty$

     { "empty volume in " cite$ * "'s crossref of " * crossref * warning$

       word.in

     }

     { bbl.volume capitalize

       volume tie.or.space.connect

       bbl.of space.word *

     }

   if$

   " \cite{" * crossref * "}" *

 }

 FUNCTION {format.incoll.inproc.crossref}

 {

   word.in

   " \cite{" * crossref * "}" *

 }

 FUNCTION {format.org.or.pub}

 { 't :=

   ""

   address empty$ t empty$ and

     'skip$

     {

       t empty$

         { address empty$

           'skip$

           { address * }

           if$

         }

         { t *

           address empty$

             'skip$

             { ", " * address * }

           if$

         }

       if$

     }

   if$

 }

 FUNCTION {format.publisher.address}

 { publisher empty$

     { "empty publisher in " cite$ * warning$

       ""

     }

     { publisher }

   if$

   format.org.or.pub

 }

 FUNCTION {format.organization.address}

 { organization empty$

     { "" }

     { organization }

   if$

   format.org.or.pub

 }

 FUNCTION {article}

 { output.bibitem

   format.authors "author" output.check

   author format.key output

   format.date "year" output.check

   date.block

   format.title "title" output.check

   new.sentence

   crossref missing$

     { journal

       "journal" output.check

 %%SP 2001/01/23

 %% Add the space in format.vol.num.pages

       %% add.blank

   before.all 'output.state :=

       format.vol.num.pages output

     }

     { format.article.crossref output.nonnull

       format.pages output

     }

   if$

   format.journal.pages

   format.note output

   fin.entry

   write.url

 }

 FUNCTION {book}

 { output.bibitem

   author empty$

     { format.editors "author and editor" output.check

       editor format.key output

     }

     { format.authors output.nonnull

       crossref missing$

         { "author and editor" editor either.or.check }

         'skip$

       if$

     }

   if$

   format.date "year" output.check

   date.block

   format.btitle "title" output.check

   crossref missing$

     { format.edition output

       new.sentence

   format.bvolume output

       format.number.series output

       new.sentence

       format.publisher.address output

     }

     {

   new.sentence

       format.book.crossref output.nonnull

     }

   if$

   format.note output

   fin.entry

   write.url

 }

 FUNCTION {booklet}

 { output.bibitem

   format.authors output

   author format.key output

   format.date "year" output.check

   date.block

   format.title "title" output.check

   new.sentence

   howpublished output

   address output

   format.note output

   fin.entry

   write.url

 }

 FUNCTION {inbook}

 { output.bibitem

   author empty$

     { format.editors "author and editor" output.check

       editor format.key output

     }

     { format.authors output.nonnull

       crossref missing$

         { "author and editor" editor either.or.check }

         'skip$

       if$

     }

   if$

   format.date "year" output.check

   date.block

   format.btitle "title" output.check

   crossref missing$

     {

       format.edition output

       new.sentence

       format.bvolume output

       format.number.series output

       new.sentence

       format.publisher.address output

       format.chapter.pages "chapter and pages" output.check

     }

     {

       format.chapter.pages "chapter and pages" output.check

   new.sentence

       format.book.crossref output.nonnull

     }

   if$

   format.pages "pages" output.check

   format.note output

   fin.entry

   write.url

 }

 FUNCTION {incollection}

 { output.bibitem

   format.authors "author" output.check

   author format.key output

   format.date "year" output.check

   date.block

   format.title "title" output.check

   new.sentence

   crossref missing$

     { format.in.ed.booktitle "booktitle" output.check

       format.edition output

       new.sentence

       format.bvolume output

       format.number.series output

       new.sentence

       format.publisher.address output

       format.chapter.pages output

     }

     { format.incoll.inproc.crossref output.nonnull

       format.chapter.pages output

     }

   if$

   format.pages "pages" output.check

   format.note output

   fin.entry

   write.url

 }

 FUNCTION {inproceedings}

 { output.bibitem

   format.authors "author" output.check

   author format.key output

   format.date "year" output.check

   date.block

   format.title "title" output.check

   new.sentence

   crossref missing$

     { format.in.ed.booktitle "booktitle" output.check

       format.edition output

       new.sentence

       format.bvolume output

       format.number.series output

       new.sentence

       publisher empty$

         { format.organization.address output }

         { organization output

           format.publisher.address output

         }

       if$

 %%SP 2001/01/23

 %%      format.pages output

     }

     { format.incoll.inproc.crossref output.nonnull

 %%SP 2001/01/23

 %%      format.pages output

     }

   if$

 %%SP 2001/01/23

   format.pages "pages" output.check

   format.note output

   fin.entry

   write.url

 }

 FUNCTION {conference} { inproceedings }

 FUNCTION {manual}

 { output.bibitem

   format.authors output

   author format.key output

   format.date "year" output.check

   date.block

   format.btitle "title" output.check

   new.sentence

   organization output

   address output

   format.edition output

   format.note output

   fin.entry

   write.url

 }

 FUNCTION {mastersthesis}

 { output.bibitem

   format.authors "author" output.check

   author format.key output

   format.date "year" output.check

   date.block

   format.title "title" output.check

   new.sentence

   bbl.mthesis format.thesis.type output.nonnull

   school "school" output.check