natbib does not show year

I'm using natbib and plainnat as bibliography style.

\documentclass[a4paper,12pt]{report}
\usepackage[T1]{fontenc}
\usepackage[round]{natbib}
\usepackage[spanish]{babel}
\usepackage[utf8]{inputenc}
\begin{document}
\citet{DIJKSTRA1959}
\bibliographystyle{plainnat}
\bibliography{mybib}
\end{document}


where mybib.bib contains

@article{DIJKSTRA1959,
author    = {Dijkstra, E. W.},
title     = {A note on two problems in connection with graphs},
journal   = {Numer. Math.},
pages     = {269-271}
year      = {1959},
volume    = 1
}


I don't know why \citet{DIJKSTRA1959} not print the year. The result is:

Dijkstra

E. W. Dijkstra. A note on two problems in connection with graphs. Numer.Math., pages 269271.

Is there a problem with the word "note" in the article's title

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Welcome to TeX.sx! You're missing a comma after pages={269-271} –  egreg Jan 11 '13 at 21:43

When you do

pdflatex file
bibtex file


you get an error from BibTeX:

The style file: plainnat.bst
Database file #1: mybib.bib
I was expecting a ,' or a }'---line 6 of file mybib.bib
:
:    year      = {1959},
(Error may have been on previous line)
I'm skipping whatever remains of this entry
Warning--empty year in DIJKSTRA1959
Warning--empty year in DIJKSTRA1959


and indeed the .bbl file shows

\bibitem[Dijkstra()]{DIJKSTRA1959}
E.~W. Dijkstra.
\newblock A note on two problems in connection with graphs.
\newblock \emph{Numer. Math.}, pages 269--271.


but only because of the error. If you add the missing comma at the end of the pages field

@article{DIJKSTRA1959,
author    = {Dijkstra, E. W.},
title     = {A note on two problems in connection with graphs},
journal   = {Numer. Math.},
pages     = {269-271},
year      = {1959},
volume    = 1
}


there will be no error by BibTeX and the .bbl file will have

\bibitem[Dijkstra(1959)]{DIJKSTRA1959}
E.~W. Dijkstra.
\newblock A note on two problems in connection with graphs.
\newblock \emph{Numer. Math.}, 1:\penalty0 269--271, 1959.


so that natbib will give the correct result for the citation, to wit

and also for the reference

Moral

Always end fields in the .bib files with a comma.

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