\cite{selbst gewählter Bibtextkey}\documentclass[12pt,a4paper]{report}
% Define language
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}
% allow images in the document
\usepackage{graphicx}
\usepackage[paper=a4paper,left=35mm,right=35mm]{geometry}
% Needed for math envrionments
\usepackage{amsmath}
\usepackage{amssymb}
% pretty tables
\usepackage{booktabs}
%Define Funktion
\DeclareMathOperator\erf{erf}
%units
\usepackage{siunitx}
\sisetup{load-configurations = abbreviations}
%bib
\usepackage{natbib}
\bibliographystyle{unsrt}
\usepackage{url}
%pdf embeding
\usepackage{pdfpages}
%Querformat
\usepackage{pdflscape}
%Chapter
\usepackage[style]{fncychap}
%Bildunterschrift kleiner
\usepackage[font=footnotesize]{caption}
\ChNameUpperCase
\ChNameVar{\raggedleft\normalsize\rm}
\ChRuleWidth{1pt}
\ChTitleUpperCase
\ChNumVar{\raggedleft \bfseries\Large}
\ChTitleVar{\raggedleft \Large\rm}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
\includepdf[pages={1}]{FP_Deckblatt}
\tableofcontents
\include{chaptors/einleitung}
\include{chaptors/grundlagen_neu}
\include{chaptors/aufgabe}
\include{chaptors/ausblick}
\appendix
\newpage
\include{chaptors/anhang}
\bibliographystyle{alpha}
\bibliography{lit_test}
\end{document}
[\code]
Danke vorab für jede hilfe
