documentclass[a4paper,12pt,headsepline]{scrartcl}

usepackage[T1]{fontenc}
usepackage{paratype}
usepackage{fix-cm}
usepackage[utf8]{inputenc}
usepackage[T1]{fontenc}
usepackage{fancybox}



usepackage{fancyhdr}
pagestyle{fancy}
fancyhf{}
fancyhead[L]{nouppercase{leftmark}}
fancyhead[C]{}
fancyhead[R]{thepage}
renewcommand{headrulewidth}{0.4pt}


usepackage[xindy]{glossaries}
makeglossaries
letglossary


usepackage{natbib, bibentry}

bibliographystyle{plain}



usepackage{setspace}


usepackage{capt-of}


usepackage{makeidx}

usepackage[english]{babel}


makeindex


usepackage[english]{nomencl}
letabbrevnomenclature



renewcommand{nomname}{List of Abbreviations}
setlength{nomlabelwidth}{.25hsize}
renewcommand{nomlabel}[1]{#1 dotfill}
setlength{nomitemsep}{-parsep}
makenomenclature


usepackage{bibentry}


begin{document}



nobibliography*
bibliography{bib}
input{glossary}


fancyhead[L]{Glossary}
%glsaddall
printglossaries
addcontentsline{toc}{section}{Glossary}





section{Document}
gls{first example}footnote{bibentry{firstexample}cite{firstexample}}.
gls{second example}



end{document}

newglossaryentry{first example}
{
  name=first example,
  description={this is the first example where the reference is also referenced in the main file footnote{bibentry{firstexample}cite{firstexample}}.}
}
newglossaryentry{second example}
{
  name=second example,
  description={this is the second example where the reference is not reference in the main file and does not appear here footnote{bibentry{secondexample}cite{secondexample}}.}
}

@article{firstexample,
  author = "Example, First",
  year = "2018",
  title = "{F}irst {E}xample",
  journal = " ",
  volume = "",
  pages = ""
}

@article{secondexample,
  author = "Example, Second",
  year = "2018",
  title = "{S}econd {E}xample",
  journal = " ",
  volume = "",
  pages = ""
}

@article{thirdexample,
  author = "Example, Third",
  year = "2018",
  title = "{T}hird {E}xample",
  journal = " ",
  volume = "",
  pages = ""
}