Customize appearence of citation of a specific bibliographic entry when using the alpha bibliography style

Question

I use bibtex with \bibliographystyle{alpha}

It works fine. My issue is with the following item.

@book{sga1,
       key = {{SGA1}},
     TITLE = {Rev\^etements \'etales et groupe fondamental},
     NOTE = {S{\'e}minaire de G{\'e}om{\'e}trie Alg{\'e}brique du Bois
          Marie 1960--1961 (SGA 1),
          Dirig{\'e} par Alexandre Grothendieck. Augment{\'e} de deux
          expos{\'e}s de M. Raynaud,
          Lecture Notes in Mathematics, Vol. 224},
     PUBLISHER = {Springer-Verlag},
     ADDRESS = {Berlin},
     YEAR = {1971},
     PAGES = {xxii+447},
 }

The tradition is to call this book SGA1. But in the text, it appears as SGA71, which is logical, but ugly. Is there a way to customize this specific item so that it appears as SGA1 in the text, without modifying its year?

Answer 1

The following works. We create a new style, that uses mylabel as a label if present, and the default alpha label otherwise

1. Find file alpha.bst (on my machine it's in directory <TEXMF>/bibtex/bst/base) and create a copy named alpha2.bst in your working directory.

2. Open the file in any editor.

3. At the beginning, there's a long list named ENTRY{...}, add there one more line:

   mylabel
   

4. The find FUNCTION {output.bibitem} (in my version it's on line 86) and modify it as follows:

   FUNCTION {output.bibitem}
   { newline$
     "\bibitem[" write$
     mylabel empty$ 'label 'mylabel if$ write$
     "]{" write$
     cite$ write$
     "}" write$
     newline$
     ""
     before.all 'output.state :=
   }
   

5. Save an close the file.

6. Open your .bib file, and add to your entry:

   mylabel={SGA1},
   

7. In your .tex file, change your style to \bibliographystyle{alpha2}.

8. Run latex, bibtex, latex, latex.

9. Happy TeXing!