main.tex

\documentclass{article}

%
% Packages
%
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage[hidelinks]{hyperref}
\usepackage{csquotes}
\usepackage{breqn} % dmath: parentheses over multiple lines

% Bibliography
\usepackage[backend=biber, style=numeric, sorting=nyt, backref=true, hyperref=true, defernumbers=true]{biblatex}
% capitalize titles 
\usepackage{mfirstuc-english} % for \capitalisewords
\DeclareFieldFormat[article,inbook,incollection,inproceedings,patent,thesis,unpublished]{title}{\capitalisewords{#1}}
\addbibresource{bibliography.bib}
\addbibresource{ISASPublikationen.bib}
%\addbibresource{paperlocal.bib}

% Mark own publications by keyword
\DeclareSourcemap{
  \maps[datatype=bibtex]{
    \map{
      \step[fieldsource=author, match=Frisch, final]
      \step[fieldset=keywords, fieldvalue=own]
    }
  }
}


%
% User-Defined Files
%
\input{abbreviations1}
\input{acronyms}

\begin{document}

%
% Content
%
test

% \usepackage{breqn}
\begin{dmath}
a\paren{\int_0^1 \\ x^2}
\end{dmath}

% Print ALL references in bib files
\nocite{*} % too much if ISASPublications.bib is enabled! 

\cite{Kalman1960_ANewApproachToLinearFilteringAndPredictionProblems, Daum2008_ParticleFlowForNonlinearFiltersWithLogHomotopy}
\cite{Frisch2021_DeterministicSamplingOnTheCircleUsingProjectedCumulativeDistributions}
\cite{JAIF23_Frisch}


%
% Own Publications
%
\newrefcontext[labelprefix=O]
\printbibliography[keyword=own, heading=bibintoc, resetnumbers=true]

%
% Bibliography
%
%\newrefcontext[labelprefix={}]
%\printbibliography[notkeyword=own, resetnumbers=true, heading=subbibintoc, title={Bibliography}]


\end{document}