How to limit number of authors in square brackets in alphabetic biblatex style?

Question

I'm using biblatex with the alphabetic style.

If there are multiple authors it takes the first Letter of every author (first example), but I'd like to have just the first author (second example, but also if there would be multiple authors) - how can I achieve this? I was not able to find the according option in biblatex.

Though there would be a doubling, both notations in the square brackets should be the same in this case.

other example:

should be [Box60] and [Box51].

My minimal example:

\documentclass{article}
\usepackage[backend=bibtex,style=alphabetic]{biblatex}

\begin{filecontents}{references.bib}
@ARTICLE{boxwilson, 
author={Box, G. E. P. and Wilson, K. B. }, 
journal={Journal of the Royal Statistical Society. Series B (Methodological)}, 
title={On the Experimental Attainment of Optimum Conditions}, 
year={1951}, 
volume={13}, 
number={1}, 
pages={1-45}, 
,}
}
\end{filecontents}


\bibliography{references.bib} 
\begin{document}
\cite{boxwilson}
\printbibliography
\end{document}

A distinction between doubled entries is alright: [Box60a] and [Box60b].

Thank you!

---

Edit:

Any Biblatex with bibtex backend solution would still be appreciated!

Best biber solution I finally found.

Answer 1

This can be done with \DeclareLabelalphaTemplate. This command is only available with Biber though, so you will have to switch backends.

First we get rid of a "et al."/and others marker by \renewcommand*{\labelalphaothers}{}. Then we define

\DeclareLabelalphaTemplate{
  \labelelement{
    \field[final]{shorthand}
    \field{label}
    \field[strwidth=3,strside=left,names=1]{labelname}
  }
  \labelelement{
    \field[strwidth=2,strside=right]{year}    
  }
}

To only take the first three letters of the first author's name and go with that as the name part if the label.

This will disambiguate labels that would be ambiguous by adding letters though; if you cannot live with that feature, try

\DeclareFieldFormat{extraalpha}{}

MWE

\documentclass{article}
\usepackage[backend=biber,style=alphabetic]{biblatex}
\usepackage{filecontents}
\begin{filecontents*}{\jobname.bib}
@ARTICLE{boxwilson, 
  author={Box, G. E. P. and Wilson, K. B.}, 
  journal={Journal of the Royal Statistical Society. Series B (Methodological)}, 
  title={On the Experimental Attainment of Optimum Conditions}, 
  year={1951}, 
  volume={13}, 
  number={1}, 
  pages={1-45}, 
}
@ARTICLE{boxwilson60, 
  author={Box, G. E. P. and Behnken, D. W.}, 
  journal={Some Journal}, 
  title={Torque Analysis}, 
  year={1960}, 
  volume={12}, 
  number={1}, 
  pages={1-45}, 
}
\end{filecontents*}

\renewcommand*{\labelalphaothers}{}

\DeclareLabelalphaTemplate{
  \labelelement{
    \field[final]{shorthand}
    \field{label}
    \field[strwidth=3,strside=left,names=1]{labelname}
  }
  \labelelement{
    \field[strwidth=2,strside=right]{year}    
  }
}

\bibliography{\jobname.bib} 
\begin{document}
\cite{boxwilson,boxwilson60}
\printbibliography
\end{document}