! LaTeX Error: Missing \begin{document}.
See the LaTeX manual or LaTeX Companion for explanation.
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...
l.1 \begin{thebibliography}{}
This is BibTeX, Version 0.99d (TeX Live 2015) The top-level auxiliary file: Vorlage.aux The style file: alphadin.bst I found no \bibdata command---while reading file Vorlage.aux Warning--I didn't find a database entry for "howi" (There was 1 error message)
Danach folgen weitere Probleme.
Hier das Beispiel:
% -------------
% Präambel
% -------------
\documentclass[12pt,a4paper,ngerman,]{scrartcl}
% ------------------
% Pakete laden
% ------------------
% -------------
% Schriftart
% -------------
\usepackage [T1]{fontenc}
\usepackage [utf8]{inputenc}
\usepackage {babel}
\usepackage{lmodern}
\usepackage{microtype}
%\setlength{\emergencystretch}{1em}
\usepackage[scaled]{helvet}
% ----------------------
% Seitengeometrie
% ----------------------
\usepackage{geometry}
\geometry{a4paper, top=27mm, left=30mm, right=20mm, bottom=35mm, headsep=10mm, footskip=12mm}
% -------------------------
%Chemie und Mathe
% -------------------------
\usepackage {siunitx}
\usepackage{chemformula}
\usepackage[version=4]{mhchem}
%------
% Links
%------
\usepackage {url}
\urlstyle{same}
\usepackage{mdwlist}
\usepackage{paralist}
\usepackage{graphicx}
\usepackage{tabularx}
\usepackage{subfigure}
% ----------------------
%Literaturquellen
% ----------------------
\usepackage[babel, german=quotes]{csquotes}
%\usepackage[style=science]{biblatex}
\usepackage[super]{cite}
\bibliography{Quellen}
\bibliographystyle{alphadin}
% ----------------------
% Nummerierung
% ----------------------
\setcounter{secnumdepth}{2}
% -----------------------------
% Tabellen und Grafiken
% -----------------------------
%Bildunterschriften
\usepackage{caption}
\usepackage[labelfont=bf,font={small,sf}]{caption}
\addto\captionsngerman{\renewcommand{\figurename}{Abb.}}
%Für Tabellen:
%\addto\captionsngerman{\renewcommand{\tablename}{Tab.}
% -------------
% Kopfzeile
% -------------
\usepackage{scrlayer-scrpage}
%\usepackage[headtopline,headsepline]{scrlayer-scrpage}
%\setheadtopline{0,4pt}
%\setheadsepline{}
\clearscrheadfoot
\ihead{}
\ohead{14.06.2016}
\ifoot*{}
\ofoot{\pagemark}
\pagestyle{scrheadings}
\setkomafont{pageheadfoot}{\small}
\setkomafont{pagehead}{}
%\bfseries
\addto\captionsngerman{\renewcommand{\headfont}{\fontfamily{phv}\selectfont}}
%\renewcommand{\pnumfont}{\fontfamily{phv}\selectfont}
%---------------------------------------------------------------------------------------------------------
% Dokument
%---------------------------------------------------------------------------------------------------------
\begin{document}
%\sloppy
%----------------------------------------------------------------------------------------------------------
% Titelseite
%---------------------------------------------------------------------------------------------------------
\thispagestyle{empty}
\large\normalfont Assistent (Datum, Unterschrift):
\vspace{2.0cm}
\begin{center}
\parbox{\linewidth}{\phantom{sdfdf}}
\par
\bfseries \huge Darstellung von ..
\vspace{0.1cm}
\normalfont \\
\vspace{1.1cm}
\bfseries\large Protokoll zum Anorganisch-Chemischen Grundpraktikum II:\\
\vspace{0.1cm}
Anorganische Präparate\\
\vspace{0.1cm}
(Modul chem0205)\\
\vspace{1.1cm}
\large\normalfont Unter der Anleitung von\\
\vspace{0.1cm}
\bfseries ... \\
\vspace{1.1cm}
\large\normalfont Bearbeitet und vorgelegt von\\
\vspace{0.1cm}
\bfseries und\\
\vspace{0.1cm}
\bfseries Gruppe \\
\vspace{1.1cm}
series\textsc{...Universität..}\\
\vspace{0.1cm}
\bfseries SoSe
\end{center}
\pagebreak
%--------------------------
%Zusammenfassung
%--------------------------
\section{Zusammenfasung}
Test \cite{howi}
%------------
%Literatur
%------------
\printbibliography
%\theendnotes
\end{document}
