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I've properly set the reference in the .bib file but still getting author problems:

Author undefined for the 'baeza1999modern' on page 1

In my ref.bib, I do have an entry:

  title={Modern information retrieval},
  author={Baeza-Yates, Ricardo and Ribeiro-Neto, Berthier and others},
  publisher={ACM press New York.}

In LaTeX, the text is

As coupled by ~\citet{baeza1999modern},

I want to get something like Baeza-Yates et al.. However, it is appearing like

enter image description here

The error I am getting is

Author undefined for citation`baeza1999modern' (natbib) on page 1

Any idea?

Ok, currently I have a solution which allow me at least to continue working,

I added this in the preamble,

\usepackage[numbers, square]{natbib}

and this \bibliographystyle{plainnat}.

So, currently the et al is being displayed properly, the citation is appearing like [2,1].

It would have been better if it was like [Sin01,ADV10]; any suggestion?

share|improve this question
Are you running the usual sequence latex, bibtex, latex, latex on your file? (I'd also change the ... by ~\citet to ... by~\citet, but that is only for aesthetic reasons.) – jon Mar 10 '13 at 21:48
for the 4 commands you listed, is not there a single command that does all, actually, i'm using texmaker – Noor Mar 10 '13 at 21:52
According to LaTeX Editors/IDEs, it's unsure whether TeXmaker has a project manager. However, it does seem to distinguish between a "Quick Build" and "something else." That something else, I assume, would allow you to compile using a sequence that could include bibtex. – Werner Mar 10 '13 at 22:00
For automatic compilation, see tex.stackexchange.com/questions/64/… Latexmk and arara. You could also set up a quick build or user command that runs all four. – Torbjørn T. Mar 10 '13 at 22:01
Your posted example complies fine in a standard set-up. Please post a complete minimal working example (MWE), rather than code snippets. – Andrew Swann Mar 11 '13 at 12:39

A standard working set-up would be



As coupled by~\citet{baeza1999modern}, or perahps \citeauthor{baeza1999modern}.



with ref.bib as in your question. This gives

Sample output

share|improve this answer
Suppose then I want to only use use \cite, how does it appear?? if i'm not mistaken, the whole et al appear then?? – Noor Mar 11 '13 at 17:05
\cite behaves as \citet in this scheme. The documentation of natbib advises against using \cite, suggesting that you should always use either \citet or \citep as appropriate. – Andrew Swann Mar 11 '13 at 17:13

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