Changes to make to enumerate references in bibliography?

Question

I could finally get the the code for references in bibliography. But the numbers do no seem to appear whatever I try. What changes do I make in the following code ? There are few extra packages, please ignore them.

\documentclass[12pt,twoside,a4paper]{report}
%\documentclass[12pt,twoside,a4paper,draft]{report}
\author{S Sudheer}

\usepackage[bookmarksnumbered,colorlinks=true,citecolor=blue,linkcolor=blue,urlcolor=blue]{hyperref}
%\usepackage[bookmarksnumbered,colorlinks=true,citecolor=black,linkcolor=black,urlcolor=black]{hyperref}

\usepackage{abstract}
\renewcommand{\abstractnamefont}{\normalfont\Huge\bfseries}
%\renewcommand{\abstracttextfont}{\normalfont\Huge}

\usepackage[hmarginratio=1:1]{geometry}
\usepackage{abstract,graphicx,color,float,amsmath,relsize,url,bm}
\usepackage[titletoc,page]{appendix}

\usepackage[raggedright]{titlesec}
\titlespacing{\section}{0pt}{1pt plus 1pt minus 1pt}{-1pt plus 1pt minus 1pt}
\titlespacing{\subsection}{0pt}{1pt plus 1pt minus 1pt}{-1pt plus 1pt minus 1pt}
\titlespacing{\subsubsection}{0pt}{1pt plus 1pt minus 1pt}{-1pt plus 1pt minus 1pt}
%\newcommand\section{\@startsection {section}{1}{\z@}%
%                                   {-3.5ex \@plus -1ex \@minus -.2ex}%
%                                   {2.3ex \@plus.2ex}%
%                                   {\normalfont\Large\bfseries\raggedright}}


\usepackage{tabularx,multirow,array}
\usepackage{cleveref} % Load AFTER hyperref!
    \crefname{equation}{Eq.}{Eqs.}
    \Crefname{equation}{Equation}{Equations}
    \crefname{figure}{Fig.}{Figs.}
    \Crefname{figure}{Figure}{Figures}
    \crefname{table}{Table}{Tables}
    \Crefname{table}{Table}{Tables}
    \crefname{section}{Section}{Sections}
    \Crefname{section}{Section}{Sections}
    \crefname{chapter}{Chapter}{Chapters}
    \Crefname{chapter}{Chapter}{Chapters}
%   \Crefname{chapter}{Chapter}{Chapters}
%   \Crefname{appendix}{Appendix}{Appendices}
%   \crefformat{appendices}{Appendix~(#2#1#3)}
%   \Crefformat{app}{#2Appendix~(#1)#3}
%   \crefformat{app}{#2Appendix~(#1)#3}
%   \Crefformat{appendix}{\appendixname~#2#1#3}
%End of Clever Ref Package

\usepackage[justification=centering,labelfont=bf,labelsep=space]{caption}
%\usepackage[justification=centering,font=small,labelfont=bf,labelsep=space]{caption}
\captionsetup{%
    figurename=Fig.
%%  tablename=Tab.
}

%float extra space removal
% Alter some LaTeX defaults for better treatment of figures:
    \renewcommand{\topfraction}{1}  % max fraction of floats at top
    \renewcommand{\bottomfraction}{1}   % max fraction of floats at bottom
    %   Parameters for TEXT pages (not float pages)
    \setcounter{topnumber}{2}
    \setcounter{bottomnumber}{2}
    \setcounter{totalnumber}{4}     % 2 may work better
    %\setcounter{dbltopnumber}{2}    % for 2-column pages
    %\renewcommand{\dbltopfraction}{0.9}    % fit big float above 2-col. text
    \renewcommand{\textfraction}{0.01}  % allow minimal text w. figs
    %   Parameters for FLOAT pages (not text pages)
    \renewcommand{\floatpagefraction}{0.7}  % require fuller float pages MUST be less than topfraction !!
    %\renewcommand{\dblfloatpagefraction}{0.7}  % require fuller float pages
    % remember to use [htp] or [htpb] for placement
%end of extra space removal

%Page and paragraph Setup
\usepackage{parskip}
    \topmargin -0.3in
    \headheight 14.5pt
    \headsep 0.3in
    \textheight 9.4in
    \oddsidemargin 0.15in
    \evensidemargin -0.15in
    \textwidth 6.3in
    \raggedbottom
    \parskip 10pt %4pt  %6.2pt                  % sets spacing between paragraphs
    \renewcommand{\baselinestretch}{1.2}    % Uncomment for 1.5 spacing between lines
    \parindent 0pt                  % sets leading space for paragraphs 
%End of page setup

%widows and orphans
%\widowpenalty=300
%\clubpenalty=300

\usepackage[Sonny]{fncychap}
%Instead of Sonny you can try one of these: Lenny, Glenn, Conny, Rejne and Bjarne
\usepackage{fancyhdr}
    \makeatletter
    \def\headrule{{%
      \if@fancyplain\let\headrulewidth\plainheadrulewidth\fi
      \hrule\@height\footrulewidth\@width\headwidth\vskip1pt%
      \hrule\@height\headrulewidth\@width\headwidth\vskip-\headrulewidth\vskip-4pt
    }}
    %
%   \def\footrule{{%
%     \if@fancyplain\let\footrulewidth\plainfootrulewidth\fi
%     \vskip-\footruleskip\vskip-\footrulewidth
%     \hrule\@height\headrulewidth\@width\headwidth\vskip1pt%
%     \hrule\@height\footrulewidth\@width\headwidth\vskip\footruleskip
%   }}
    \makeatother

% Long title in TOC and short in header for chapters
    \makeatletter
        \newcommand*\std@chapter{}
        \let\std@chapter=\@chapter
        \renewcommand*\@chapter[2][]{\std@chapter[#2]{#2}\chaptermark{#1}}
    \makeatother

    \pagestyle{fancy}
    %\setlength{\headheight}{15pt}
    \renewcommand{\chaptermark}[1]{\markboth{\thechapter.\ #1}{}}
    \lhead[{\fancyplain{}{\textit{\nouppercase\leftmark}}}]{}
    \rhead[]{\fancyplain{}{\textit{\nouppercase\leftmark}}}
    \lfoot[\thepage]{}
    \rfoot[]{\thepage}
    \cfoot{}
    \renewcommand{\headrulewidth}{0.5pt}
    \renewcommand{\footrulewidth}{0.5pt}

    \fancypagestyle{plain}{ %
    \lhead{} % remove everything
    \chead{}
    \rhead{}
    \lfoot{}
    \cfoot{\thepage}
    \rfoot{}
    \renewcommand{\headrulewidth}{0pt} % remove lines as well
    \renewcommand{\footrulewidth}{0pt}}
%end of page style

%\usepackage[utf8]{inputenc}
\usepackage{nomencl}
\makenomenclature
\RequirePackage{ifthen} 
\renewcommand{\nomgroup}[1]{% 
  \ifthenelse{\equal{#1}{A}}{\item[\textbf{Variables}]}{% 
    \ifthenelse{\equal{#1}{G}}{\item[\textbf{Greek Symbols}]}{%{}}} 
      \ifthenelse{\equal{#1}{S}}{\item[\textbf{Subscripts}]}{%}}}}  Suffixes
        \ifthenelse{\equal{#1}{T}}{\item[\textbf{Acronyms}]} 
{}}}}}

%Sample nomenclature
%\nomenclature[a]{$a$}{The number of angles per unit area}%
%\nomenclature[g]{$\alpha$}{Absorptivity}
%\nomenclature[s]{i}{Initial}
%\nomenclature[t]{$IND$}{INDIA}

% NATBIB
\usepackage[numbers]{natbib}
\bibpunct{(}{)}{,}{a}{,}{,}

%Sample of refernce scheme
% \citet{key}  ==>>  Jones et al. (1990)           (in-text form)
% \citep{key}  ==>> (Jones et al., 1990)           (parenthetical form)
% \citep{key1,key2}         ==>> (Jones et al., 1990, 1992)
% (multiple citations; common authors suppressed)
% \citep[chap. 2]{key}      ==>> (Jones et al., 1990, chap. 2)
% \citep[see][]{key}        ==>> (see Jones et al., 1990)
% \citep[see][chap. 2]{key} ==>> (see Jones et al., 1990, chap. 2)

\usepackage{bookmark}
\newcommand\norm[1]{\left\lVert#1\right\rVert}
\newcommand{\xrightarrowdbl}[2][]{%
    \leftarrow\mathrel{\mkern-14mu}\xrightarrow[#1]{#2}
}
\usepackage{tikz-cd}
%\newcommand{\nospaceperiod}{\makebox[0pt][l]{\,}}
\usepackage{adjustbox}
\usepackage{caption}
\usepackage{subcaption}
\usepackage{amsfonts,amsmath,amssymb,bbm,amsthm}
\usepackage[english]{babel}
\newtheorem{theorem}{Theorem}


\begin{document}

    \input{content}

\end{document}     

I have created a file by name content.tex where I have input the bibliography.bib file. This is the code in .bib file

  @Book{planningalgorithms,
  author = "LaValle, Steven M",
  title = "{Planning Algorithms}",
  publisher = {Cambridge Univ. Press},
  year = "2006",
  pages = "1--570"
  }


   @Book{springer,
  author = "Lydia E Kavraki and Steven M LaValle",
  title = "{Springer handbook of Robotics}",
  publisher = {Cambridge Univ. Press},
  year = "2002",
  Place = "Cambridge",
  }


  @conference{cd10,
  author = "carlsson, Gunnar  and Silva, Vin ",
  title = "{Zigzag persistence}",
  booktitle = "{Foundations of Computational mathematics}",
  year = "2010",
  } 

 @article{dg06,
  author = "Vin De Silva and Robert Ghrist ",
  title = "{Coordinate-free coverage in sensor networks with controlled boundaries via homology.}",
  journal = "{International Journal of Robotics Eesearch}",
  year = "2006",
  }

  @Book{hat02,
  author = "Allen Hatcher",
  title = "{Algebraic Topology}",
  publisher = {Cambridge Univ. Press},
  year = "2002",
  Place = "Cambridge",
  }


  @article{kal13,
  author = "Sara Kalisnik",
  title = "{Alexander Duality for Parametrized Homology}",
  journal = "{Homology, Homotopy and Applications}",
  year = "2013",
  }

  @article{adams,
  author = "Henry Adams and Gunnar Carlsson",
  title = "{Evasion Paths in Mobile Sensor Networks}",
  journal = "{International Journal of Robotics Research}",
  year = "2013",
  }

This is the output I am getting in Bibliography section

What changes can I make in the above code to get the numbers(or some other defined labels) beside the references ?