How to let the cited references have the form "authors (year)" instead of "[1]" say?

You can use the package "natbib". The following is an example:

documentclass[12pt]{article}
usepackage[super, sort]{natbib}
bibpunct{(}{)}{;}{a}{,}{,} % required for natbib

begin{document}

Use the natbib package with options texttt{super} and texttt{sort}, 
and use verb+citep+ or verb+citet+
instead of the command verb+cite+. In detail, we need to include the 
natbib package
and include the line

begin{verbatim}
bibliographystyle[super, sort]{natbib}
bibpunct{(}{)}{;}{a}{,}{,}
end{verbatim}

in the preamble. 

And use the bibliographstyle texttt{plainnat}, i.e.
verb+bibliographystyle{plainnat}+.

The command
verb+citet+ is for ``last name (year)'' and verb+citep+ for 
``(last name, year)'' which will be shown in the text.


The result of verb+citep{GoossensEtAl:1999}+ is citep{GoossensEtAl:1999}.
The result of verb+citetcitet{GoossensEtAl:1999}+ is citet{GoossensEtAl:1999}.

bibliographystyle{plainnat} % required for natbib
bibliography{workshop}

end{document}

The content of the file "

workshop.bib

" is below:

@book{GoossensEtAl:1999,
  author="{Goossens, M.} and {Rahtz, S.} with {Gurari, E., M.} and {Moore, R.} and {Sutor, R.  S.}",
  title="The LaTeX, Web Companion",
  publisher="Addison-Wesley",
  year="1999"
} 

You can copy the above two files to your computer and compile them to see the

result

.