\documentclass[a4paper]{article}
\usepackage[a4paper, total={20cm, 27cm}]{geometry}

\pagestyle{empty}

\usepackage[utf8]{inputenc}
\usepackage{hyperref}
\usepackage[
%backend=biber,
backend=bibtex,
style=reading,
sorting=ydnt,
defernumbers=true
]{biblatex}
\addbibresource{../../../../castor.bib}
\addbibresource{../../../../golem.bib}

\title{The GOLEM tokamak bibliography\\Topic: {\bf stabilization}}

\author{The tokamak GOLEM team}
%\date{}

\defbibfilter{golemarticles}{%
  ( type=article or type=thesis )
  and keyword=infr.posstab
}






\begin{document}

\maketitle

\nocite{*}


\section{GOLEM Articles}
\printbibliography[filter=golemarticles, title={}]



%\printbibliography[type=inproceedings,title={Conference proceedings}]
%\printbibliography[keyword=mathesis,title={Master thesis}]
%\printbibliography[keyword=bachproj,title={Bachelor projects}]
%\printbibliography[keyword=soc,title={High School Students` Professional Activities}]
%\printbibliography[type=misc,keyword=in, title={Miscellaneous}]
%\printbibliography[type=article,keyword=out,title={Unofficial articles (without GOLEM cooperation/authors)}]

%\printbibliography[title={The tokamak GOLEM bibliography}]

\end{document}