I have a .bib file that gets displayed in the end of my document but i wold like to add the referenced sections (with \cite(ref1)) to every corresponiding page footer automaticaly. Is that possible?
mwe:
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[greek,ngerman]{babel}
\usepackage{lastpage}
\usepackage{fancyhdr}
\pagestyle{fancy}
\renewcommand{\headrulewidth}{0.1pt}
\renewcommand{\footrulewidth}{0.1pt}
\setlength{\headheight}{16pt}
\usepackage{titlesec}
\usepackage{hyperref}
\usepackage{blindtext}
\begin{document}
\setcounter{page}{1}
\tableofcontents
\thispagestyle{empty}
\clearpage
\section{first section}
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna \cite{einstein} aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.
\footnote{\let\cite=\footcite} % <------- this is the second try
\subsection{first subsection}
\blindtext
\blindtext
\subsubsection{first subsubsection}
\blindtext
\paragraph{first paragraph}
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna \cite{latexcompanion} aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.
\let\cite=\footcite %<---------- this is the first try
\newpage
\thispagestyle{empty}
\section{References}
\begin{thebibliography}{9}
\bibitem{latexcompanion}
Michel Goossens, Frank Mittelbach, and Alexander Samarin.
\textit{The \LaTeX\ Companion}.
Addison-Wesley, Reading, Massachusetts, 1993.
\bibitem{einstein}
Albert Einstein.
\textit{Zur Elektrodynamik bewegter K{\"o}rper}. (German)
[\textit{On the electrodynamics of moving bodies}].
Annalen der Physik, 322(10):891–921, 1905.
\end{thebibliography}
\end{document}

\let\cite=\footcite– koleygr Oct 19 '17 at 07:17documentclass, some entries insidefilecontentsenvironment (if you use a .bib file) [just like the linked answer] and any package or code added in your code that may be changes the bibliography behavior. I will give you a working solution in some minutes... But if we don't get a MWE and if the code I will give you can not work for you... then there is no way to help you – koleygr Oct 19 '17 at 19:47