Cfrgtkky

I am trying to use BibTeX, but the result of this code is that it prints the Bibliography headline and does not display what's inside the sample.bib file.
Does someone recognize any mistake? Thanks

documentclass[12pt,a4paper,twoside]{book}

    setcounter{secnumdepth}{3} % number subsubsections

    setcounter{tocdepth}{3} % put subsubsections in ToC

    renewcommand{thesubsubsection}{ensuremath{blacktriangleright}} % no number, fancy glyph

usepackage{gensymb}

usepackage{listings}

usepackage{color}

usepackage{booktabs}

usepackage{amsmath}

usepackage{mathtools}

newcommandnumberthis{addtocounter{equation}{1}tag{theequation}}

usepackage{float}

restylefloat{figure}

usepackage[margin=2cm]{geometry}

usepackage[nottoc]{tocbibind}

usepackage[hang]{footmisc}

setlengthfootnotemargin{15pt}

usepackage[justification=centering]{caption}

usepackage[utf8]{inputenc}

usepackage[pdftex]{graphicx}

usepackage[english]{babel}

usepackage{fixltx2e,bold-extra,geometry,

    amssymb,amsmath,mathtools, microtype,url}

usepackage[bookmarks=true, hidelinks, pdftitle={

THE MANAGEMENT AND PRICING OF WEATHER DERIVATIVES:The case of an HDD Call Option},

pdfauthor={Alessandro Pipitone}]{hyperref}

pagestyle{headings}

graphicspath{{images/}}



%%%%%%%%%%%%%%%%% New Commands %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

lstset{ 

    language=Matlab,

    numbers=left, 

    numberstyle=footnotesize,  stepnumber=1,                               numbersep=5pt,backgroundcolor=color{white},

    showspaces=false,   showstringspaces=false,

    showtabs=false,                         frame=single,              

    tabsize=2,captionpos=b,

    breaklines=true,       

    breakatwhitespace=false,

    escapeinside={%*}{*)}  

}

%

newcommand{intentblankpage}{

%     Leaves a blank page

    newpage

    null

    vfill

    thispagestyle{empty}

    begin{center}

         textit{This page intentionally left blank.}

        %textit{Questa pagina `e lasciata intenzionalmente bianca.}

    end{center}

    newpage

}

defmclimits_#1{limits_{mathclap{#1}}}

%%%%%%%%%%%%%%%% End New Commands %%%%%%%%%%%%



begin{document}

    input{./titlepage}

    intentblankpage

    pagenumbering{Roman}

    tableofcontents



    chapter*{Introduction} pagenumbering{arabic}

    addcontentsline{toc}{chapter}{Introduction}  

    label{CH:Intro}

    input{./introduzione}



    chapter{The Weather as a Source of Risk}

    label{CH:Teoria}

    input{./capI}



    chapter{Inside the Market: How to Manage Risk Weather}

    label{CH:Val_num}

    input{./capII}



    chapter{Forecasting and Pricing models: A Focus on Temperature}

    label{CH:Val_num}

    input{./capIII}



    chapter{Numerical Implementation of Pricing Models}

    label{CH:Val_num}

    input{./capIV}



    chapter*{Conclusion} 

    addcontentsline{toc}{chapter}{Conclusion}  

    label{CH:Intro}

    input{./conclusioni}



     chapter*{Appendix A} 

    addcontentsline{toc}{chapter}{Appendix A}  

    label{CH:Intro}

    input{./Appendix}



bibliographystyle{unsrt}

bibliography{sample}





    %listoffigures

end{document}

My bib file looks like this

@article{einstein,

  author =       "Albert Einstein",

  title =        "{Zur Elektrodynamik bewegter K{"o}rper}. ({German})

                 [{On} the electrodynamics of moving bodies]",

  journal =      "Annalen der Physik",

  volume =       "322",

  number =       "10",

  pages =        "891--921",

  year =         "1905",

  DOI =          "http://dx.doi.org/10.1002/andp.19053221004"

}



@book{latexcompanion,

    author    = "Michel Goossens and Frank Mittelbach and Alexander Samarin",

    title     = "The LaTeX Companion",

    year      = "1993",

    publisher = "Addison-Wesley",

    address   = "Reading, Massachusetts"

}



@misc{knuthwebsite,

    author    = "Donald Knuth",

    title     = "Knuth: Computers and Typesetting",

    url       = "http://www-cs-faculty.stanford.edu/~{}uno/abcde.html"

}

Please see the following MWE. I added your given bib file to it with package filecontents.

Please see that you have to change the order of your used packages. Do not load packages twice.

Because we do not have your inputed files I added nocite{*} to get all bib entrys printed in the bibliography.

RequirePackage{filecontents}

begin{filecontents*}{jobname.bib}

@article{einstein,

  author =       "Albert Einstein",

  title =        "{Zur Elektrodynamik bewegter K{"o}rper}. ({German})

                 [{On} the electrodynamics of moving bodies]",

  journal =      "Annalen der Physik",

  volume =       "322",

  number =       "10",

  pages =        "891--921",

  year =         "1905",

  DOI =          "http://dx.doi.org/10.1002/andp.19053221004"

}



@book{latexcompanion,

    author    = "Michel Goossens and Frank Mittelbach and Alexander Samarin",

    title     = "The LaTeX Companion",

    year      = "1993",

    publisher = "Addison-Wesley",

    address   = "Reading, Massachusetts"

}



@misc{knuthwebsite,

    author    = "Donald Knuth",

    title     = "Knuth: Computers and Typesetting",

    url       = "http://www-cs-faculty.stanford.edu/~{}uno/abcde.html"

}

end{filecontents*}





documentclass[12pt,a4paper,twoside]{book}



usepackage[utf8]{inputenc}

usepackage[english]{babel}



setcounter{secnumdepth}{3} % number subsubsections

setcounter{tocdepth}{3} % put subsubsections in ToC

renewcommand{thesubsubsection}{ensuremath{blacktriangleright}} % no number, fancy glyph

usepackage{gensymb}

usepackage{listings}

usepackage{color}

usepackage{booktabs}

usepackage{amsmath}

usepackage{mathtools}

newcommandnumberthis{addtocounter{equation}{1}tag{theequation}}

usepackage{float}

restylefloat{figure}

usepackage[margin=2cm]{geometry}

%usepackage{csquotes} % <===============================================

%usepackage{biblatex}

%addbibresource{jobname.bib}

usepackage[hang]{footmisc}

setlengthfootnotemargin{15pt}

usepackage[justification=centering]{caption}



usepackage{graphicx} % <=======================================

usepackage{%

% fixltx2e,

  bold-extra,

% geometry,

  amssymb,mathtools, microtype,url

}

usepackage[%

  bookmarks=true, hidelinks, 

  pdftitle={THE MANAGEMENT AND PRICING OF WEATHER DERIVATIVES:The case of an HDD Call Option},

  pdfauthor={Alessandro Pipitone}

]{hyperref}

pagestyle{headings}

graphicspath{{images/}}



%%%%%%%%%%%%%%%%% New Commands %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

lstset{ 

    language=Matlab,

    numbers=left, 

    numberstyle=footnotesize,  stepnumber=1,                               numbersep=5pt,backgroundcolor=color{white},

    showspaces=false,   showstringspaces=false,

    showtabs=false,                         frame=single,              

    tabsize=2,captionpos=b,

    breaklines=true,       

    breakatwhitespace=false,

    escapeinside={%*}{*)}  

}

%

newcommand{intentblankpage}{

%     Leaves a blank page

    newpage

    null

    vfill

    thispagestyle{empty}

    begin{center}

         textit{This page intentionally left blank.}

        %textit{Questa pagina `e lasciata intenzionalmente bianca.}

    end{center}

    newpage

}

defmclimits_#1{limits_{mathclap{#1}}}

%%%%%%%%%%%%%%%% End New Commands %%%%%%%%%%%%



begin{document}

%   input{./titlepage}

    intentblankpage

    pagenumbering{Roman}

    tableofcontents



    chapter*{Introduction} pagenumbering{arabic}

    addcontentsline{toc}{chapter}{Introduction}  

    label{CH:Introc}

%   input{./introduzione}



    chapter{The Weather as a Source of Risk}

    label{CH:Teoria}

%   input{./capI}



    chapter{Inside the Market: How to Manage Risk Weather}

    label{CH:Val_num}

%   input{./capII}



    chapter{Forecasting and Pricing models: A Focus on Temperature}

    label{CH:Val_numa}

%   input{./capIII}



    chapter{Numerical Implementation of Pricing Models}

    label{CH:Val_numb}

%   input{./capIV}



    chapter*{Conclusion} 

    addcontentsline{toc}{chapter}{Conclusion}  

    label{CH:Intro}

%   input{./conclusioni}



     chapter*{Appendix A} 

    addcontentsline{toc}{chapter}{Appendix A}  

    label{CH:Introb}

%   input{./Appendix}



nocite{*} % <==========================================================

bibliographystyle{unsrt}

bibliography{jobname}



    %listoffigures

end{document}

and the resulting bibliography: