I am trying to use \citefield{soure1}{abstract} to include an abstract from my BibTeX file in my document. But, I always receive the message
Undefined control sequence.\citefield
Here is an MWE:
\RequirePackage{filecontents}
\begin{filecontents*}{\jobname.bib}
@article{authoryear,
title = {title},
author = {XY},
journal = {XY},
volume = {119},
pages = {100},
year = {2015},
url = {http://www.url.com},
abstract = {long abstract.}
}
\end{filecontents*}
\documentclass{scrartcl}
\usepackage[T1]{fontenc}
\usepackage[latin1]{inputenc}
\usepackage[top=2cm,left=1.5cm,right=1.5cm]{geometry}
\usepackage[english,german]{babel}
\usepackage[authoryear]{natbib}
\usepackage[hidelinks]{hyperref}
\pagestyle{myheadings}
\RedeclareSectionCommand[
beforeskip=-2\baselineskip,
afterskip=1\baselineskip]{section}
\RedeclareSectionCommand[
beforeskip=-1\baselineskip,
afterskip=0.5\baselineskip]{subsection}
\RedeclareSectionCommand[
beforeskip=-1\baselineskip,
afterskip=.5\baselineskip]{subsubsection}
\newenvironment{newabstract}
\begin{document}
\begin{newabstract}
\citefield{authoryear}{abstract}
\end{newabstract}
\section*{Group A}
\subsection*{\cite{authoryear} \\ \href{http://www.url.com}{title} }
\bibliography{authoryear}
\bibliographystyle{apalike}
\end{document}

\citefieldmacro? (It isn't a natbib macro for sure.) Apart from that you document needs to be reworked a little: Look up the syntax for\newenvironment,\bibliographyand\bibliographystyle. – Ruben Apr 12 '16 at 15:35\citefieldis abiblatexcommand. – JMP Apr 12 '16 at 15:38