[Tex/LaTex] TeXShop, BibDesk, URLs not shown and extra citation numbers

back-referencingbibdesktexshop

I am using TeXShop and BibDesk on Mac and even though I add "webpage" entries to BibDesk, they don't show up in TeXShop.added entry

fail

Also, I get these extra citation numbers at the end of my document:
why

when I don't have anything after the references.

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What is wrong? I have the correct packages, I think:

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EDIT: I was able to get rid of the extra reference numbers by adding a \nocite{*} and deleting the references.

FME:

\documentclass{llncs}
\usepackage{graphicx}
\usepackage{booktabs}
\usepackage{url}

\begin{document}

\nocite{*}
\bibliographystyle{plain}
\bibliography{PANs}

\end{document}

and in the PANs.bib file, I have

@article{nfcforum,
    Author = {NFC Forum},
    Date-Added = {2014-05-05 12:12:03 +0000},
    Date-Modified = {2014-05-05 13:39:56 +0000},
    Lastchecked = {5 May 2014},
    Title = {What is NFC?},
    Url = {http://nfc-forum.org/what-is-nfc/},
    Urldate = {5 May 2014},
    Year = {2014}}

Best Answer

As can be seen in ftp://ftp.springer.de/pub/tex/latex/llncs/latex2e/splncs.bst, splncs does not provide support for a url key, so it is silently ignored.

You may want to add the URL in a note field (using \url{URL}, remember to load the url package).