Hi I'm using Overleaf for my dissertation and this warning started popping up recently: Citation 'objprogen' on page 1 undefined on input line 8.
This citation is already created as seen below in the 'sources.bib' file:
@article{objprogen,
author={Guo, Wenzhong and Lin, Renjie and Wang, Shiping and Xiong, Neal},
booktitle={2018 9th International Symposium on Parallel Architectures, Algorithms and
Programming (PAAP)},
title={Object Proposal Generation for Unsupervised Object Localization},
year={2018},
volume={},
number={},
pages={235-242},
doi={10.1109/PAAP.2018.00046}}
This is my main.tex file:
\documentclass[a4paper]{article}
\usepackage{blindtext, graphicx}
\usepackage{csquotes}
\usepackage[hidelinks]{hyperref}
\usepackage{url}
\usepackage[style=authoryear-ibid,backend=biber]{biblatex}
\hyphenation{op-tical net-works semi-conduc-tor}
\bibliography{sources.bib}
\begin{document}
\title{Can image recognition systems be successfully integrated with existing VIN databases
irrespective of the vehicle manufacturer}
\author{myname}
\maketitle{}
\input{includes/01-Abstract}
\input{includes/02-Introduction}
\input{includes/03-Literature}
\input{includes/04-Methodology}
\input{includes/05-Findings}
\input{includes/06-Conclusion}
\input{includes/07-Appendix}
\end{document}
I had the same problem and solved it by adding
\bibliographystyle{plain}
(of course you could in principle use other styles). For me the structure of the tex file is the followingSo contrary to you the
\bibliography
is also inside the document environment.