4

I have googled for hours without finding any solution for my warnings. The warning says: BibTeX: warning: 1 characters of junk seen at toplevel. I have 21 working Citations in my bibliography. If i add one more, doesn't matter which one, ill get the warning (even a copied one with a eg. changed name)

@article{courbariaux2016binarized,
title={Binarized Neural Networks: Training Deep Neural Networks with Weights and Activations Constrained to +1 or -1},
author={Matthieu Courbariaux and Itay Hubara and Daniel Soudry and Ran El-Yaniv and Yoshua Bengio},
year={2016},
eprint={1602.02830},
archivePrefix={arXiv},
primaryClass={cs.LG}
}

It does not matter if I use another bibtex citation that worked already. I get the Warning for every Bibtex file. Not sure if you have enough Information to help me.

I use Natbib and Overleaf.

\documentclass[a4paper,12pt,twoside, numbers=noenddot]{scrartcl} 
\usepackage[backend=biber,natbib=true]{biblatex}
\addbibresource{literatur/bibliography.bib} 
% }
% @book{meyer2021embedded,
% title={Embedded Microprocessor System Design Using FPGAs},
% author={Meyer-Baese, Uwe},
% year={2021},
% publisher={Springer Nature},
% pages ={1}
% } 
\begin{document} 
\cite{meyer2021embedded}
\newpage
\end{document}
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  • 3
    you have something that is not in a @article{....} entry ie a non-entry text at the top level ie not inside any entty type Oct 7, 2021 at 21:10
  • Thank you for your answer. Im still unable to figure out the problem
    – Tobs
    Oct 8, 2021 at 11:15
  • provide an example that produces the error and someone will debug it. Oct 8, 2021 at 11:16
  • I just searched the entire bibtex sources and the words "junk" and "toplevel" do not appear, so it seems that you are not using bibtex but biber. Please see tex.stackexchange.com/questions/540559/… but natbib does not work with biber. Please provide an example that shows what you are doing, and what error message you got. Oct 8, 2021 at 14:57
  • \documentclass[a4paper,12pt,twoside, numbers=noenddot]{scrartcl} \usepackage[backend=biber,natbib=true]{biblatex} \addbibresource{literatur/bibliography.bib} % } % @book{meyer2021embedded, % title={Embedded Microprocessor System Design Using FPGAs}, % author={Meyer-Baese, Uwe}, % year={2021}, % publisher={Springer Nature}, % pages ={1} % } \begin{document} \cite{meyer2021embedded} \newpage \end{document} Thanks for your help :)
    – Tobs
    Oct 8, 2021 at 15:36

1 Answer 1

6

The warning is from biber (not bibtex) and generated if there are characters in the bib file that are not in an @xxx{...} entry.

For example if I take the commented entry from your tex file and save as bibliography.bib

with content

}
@book{meyer2021embedded,
title={Embedded Microprocessor System Design Using FPGAs},
author={Meyer-Baese, Uwe},
year={2021},
publisher={Springer Nature},
pages ={1}
}

Then biber will generate the output

INFO - Looking for bibtex format file 'bibliography.bib' for section 0
INFO - LaTeX decoding ...
INFO - Found BibTeX data source 'bibliography.bib'
WARN - BibTeX subsystem: /tmp/biber_tmp_ludL/f4d088b3f9f145b5c3058da33afd57d4_750.utf8, line 2, warning: 1 characters of junk seen at toplevel

This is due to the spurious } at the start of the file. Deleting it makes the warning go:

@book{meyer2021embedded,
title={Embedded Microprocessor System Design Using FPGAs},
author={Meyer-Baese, Uwe},
year={2021},
publisher={Springer Nature},
pages ={1}
} 

Note that the warning does not say what the bad characters are but does give the line number (or apparently one more than the line number) at the point the error is detected so the } on line 1 generated

line 2, warning: 1
^^^^^^^

So you should be able to find the bad characters quite easily.

3
  • Thank you very much.. I checked everything like 3 times and didn't see an additional }...
    – Tobs
    Oct 9, 2021 at 11:33
  • This was the solution for me. I had one extra { which gave the error. After removing the extra { everything is fine. May 19, 2022 at 12:25
  • Note that the line number in the warning above may be after the line that actually has the error. Moreover, the line number jumps all blank lines so it may be multiple lines after the line that actually has the error.
    – ZaydH
    Aug 27, 2022 at 0:11

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