References numbers are not shown

Question

I have a problem with my references numbers, everything looks fine in the main body of my poster but in the reference section I cannot see the numbers. Here is part of my code responsible for the bibliography:

Here is the main file:

\documentclass[final]{beamer}

%% 
\PassOptionsToPackage{english}{babel}%% 
\PassOptionsToPackage{%% Uses poster mode of class beamer --- Options
  size = custom,%% Custom Size
  width = 90,%% Width in centimeters
  height = 120,% Height in centimeters
  scale = 1.5,%% Font scale
  debug,%% Debug mode
}{beamerposter}
%% Packages used
\usepackage{utfprpgtex-poster}%% Template Styles
\usepackage{biblatex}
%% References
\AtBeginBibliography{\footnotesize}%% Font Size Small Medium Large
\addbibresource{bib.bib}%% File name

%% Document Information
\title{%% Poster title
 Calculation of the ground state energies of some nuclei using an energy-dependent potential in the cluster model%
}
\author{%% Author(s)
  Elhadj Hocine\inst{*}%
  \& Rabia Yekken%
}
\institute{%% Institute(s) and email(s)
  Département de Physique théorique, Faculté de Physique, Université des sciences et de la technologie Houari Boumediene%
  \par e-mail(s): \email[*]{[email protected]}%
}
\date{}%%

%% Document start
\begin{document}

\begin{frame}[t, fragile = singleslide]{}

\begin{columns}[t]%% Header

\begin{column}{0.02\textwidth}
\end{column}

\begin{column}{0.18\textwidth}
\flushleft
\includegraphics[width = 0.8\columnwidth]{./Logos/Logo}%% Top-left logo
\vspace*{\baselineskip}
\end{column}

\begin{column}{0.6\textwidth}
\titlepage
\end{column}

\begin{column}{0.18\textwidth}
\flushright
\includegraphics[width = 0.8\columnwidth]{./Logos/Logo}%% Top right logo
\vspace*{\baselineskip}
\end{column}

\begin{column}{0.02\textwidth}
\end{column}

\end{columns}

\begin{columns}[t]

\begin{column}{0.45\textwidth}

\begin{block}{Abstract}
Wave equations with energy-dependent potentials are well known in physics. They appear both in relativistic and non-relativistic quantum mechanics, also were used largely in particle, nuclear and atomic physics. More recently, a great interest has been brought to this type of potentials in non-relativistic quantum mechanics. Their presence in the Schrödinger wave equation generates a reformulation of the probability density to ensure the conservation of the continuity equation. The energy levels of nuclei provide an idea of their nuclear structure. Therefore, all the nuclear models, which have evolved from 1930s to now, are expected to reproduce the energy levels. One of the fundamental models of nuclear structure is the cluster
model. In the present work, we propose to calculate analytically the ground state energies of some nuclei using an energy-dependent potential in the cluster model. With a suitable parameters values, we compare the obtained results with the available experimental data.%
\end{block}

\begin{block}{The energy-dependent potentials}
In this section, we present the quantum supersymmetry, in 3 dimensional
space, extended to the case where the potentials are energy-dependent
\cite{yekken2013applying}. Starting from the generalization of the
superpotential in order to factorize the Hamiltonian $H_{n}$. Here
we have considered this notation to indicate the energy-dependence
of the Hamiltonian ($\hbar=m=e=1$)
\begin{equation}
    H_{n}=-\frac{1}{2}\nabla^{2}+V_{n}(\boldsymbol{r},E_{n}),\ \ \ n=0,1,2...,
\end{equation}
where $n$ is the radial quantum number which represents the nodes
number.
Details concerning the modifications of the usual rules of quantum
mechanics required by the energy-dependence of the potential can be
found in \cite{lombard2007wave,formanek2004wave,yekken2010energy}
(and references therein). We recall that the constraint imposed by
the continuity equation requires the density distribution to be defined
by \cite{formanek2004wave}
\begin{equation}
\rho(\boldsymbol{r},E_{n})=\psi_{n}^{*}(\boldsymbol{r},E_{n})\left[1-\frac{\partial V_{n}(\boldsymbol{r},E_{n})}{\partial E_{n}}\right]\psi_{n}(\boldsymbol{r},E_{n}).
\end{equation}
It is to note that the probability density has to be positive definite
and this is ensured if and only if
\begin{equation}
    1-\frac{\partial V_{n}(\boldsymbol{r},E_{n})}{\partial E_{n}}>0.\label{eq:positivity-condition}
\end{equation}
Accordingly, the scalar product is written as 
\begin{equation}
    \left(\psi_{n}\right|\left.\psi_{n}\right\rangle =\int\psi_{n}^{*}(\boldsymbol{r},E_{n})\left(1-\frac{\partial V_{n}(\boldsymbol{r},E_{n})}{\partial E_{n}}\right)\psi_{n}(\boldsymbol{r},E_{n})d\boldsymbol{r}.
\end{equation}
The notation $\left(\psi_{n}\right|\left.\psi_{n}\right\rangle $
is used instead of $\left\langle \psi_{n}\right|\left.\psi_{n}\right\rangle $
to distinguish the difference between the two scalar products.
\end{block}

\end{column}

\begin{column}{0.45\textwidth}

\begin{block}{MATERIAL E MÉTODOS}
A Figura~\ref{fig:campuspontagrossa} é um exemplo de figura inserida usando o ambiente \LaTeX\ ``figure'' e numerada automaticamente.
\begin{figure}[!htb]
\centering
\caption{Exemplo de legenda de figura.}
\label{fig:campuspontagrossa}
\includegraphics[width = 0.675\columnwidth]{./Figuras/campuspontagrossa}
\source{\textcite{UTFPR2018}.}
\end{figure}
A Tabela~\ref{tab:Ldimensoes} é um exemplo de tabela inserida usando o ambiente \LaTeX\ ``table'' e numerada automaticamente.
\begin{table}[!htb]
\centering\small
\caption{Exemplo de legenda de tabela.}
\label{tab:Ldimensoes}
\begin{tabular*}{\columnwidth}{@{\extracolsep{\fill}}llll}
\hline
$L$   & $L^2$     & $L^3$     & $L^4$     \\
{[m]} & {[m$^2$]} & {[m$^3$]} & {[m$^4$]} \\ \hline
1     & 1         & 1         & 1         \\
2     & 4         & 8         & 16        \\
3     & 9         & 27        & 81        \\
4     & 16        & 64        & 256       \\
5     & 25        & 125       & 625       \\ \hline
\end{tabular*}
\source{Autoria própria.}
\end{table}
Para gerar ou editar tabelas em \LaTeX\ pode-se utilizar a ferramenta ``Tables Generator'', disponível em <\url{http://www.tablesgenerator.com/}>, dentre outras.\par
Informações e dicas sobre \TeX/\LaTeX\ podem ser obtidas em:
\begin{itemize}
\item \LaTeX\ Project: <\url{http://www.latex-project.org/}>.
\item Comprehensive \TeX\ Archive Network (CTAN): <\url{http://www.ctan.org/}>.
\item \TeX\ Users Group (TUG): <\url{http://www.tug.org/}>.
\item \LaTeX\ - Wikibooks: <\url{http://en.wikibooks.org/wiki/LaTeX/}>.
\item \TeX\ - \LaTeX\ Stack Exchange: <\url{http://tex.stackexchange.com/}>.
\end{itemize}
\end{block}

\end{column}

\end{columns}

\begin{columns}[t]

\begin{column}{0.945\textwidth}

\begin{block}{RESULTADOS E DISCUSSÃO}
As Figuras~\ref{fig:graficoxy1}, \ref{fig:graficoxy2} e \ref{fig:graficoxy3} são mais exemplos de figuras inseridas usando o ambiente \LaTeX\ ``figure'' e dispostas em três colunas.
\begin{column}[T]{0.33\textwidth}
\begin{figure}[!htb]
\centering
\caption{Exemplo de legenda de figura.}
\label{fig:graficoxy1}
\includegraphics[width = 0.75\columnwidth]{./Figuras/graficoxy}
\source{Autoria própria.}
\end{figure}
\end{column}
{\color{Blue}\vrule width 1.5pt}
\begin{column}[T]{0.33\textwidth}
\begin{figure}[!htb]
\centering
\caption{Exemplo de legenda de figura.}
\label{fig:graficoxy2}
\includegraphics[width = 0.75\columnwidth]{./Figuras/graficoxy}
\source{Autoria própria.}
\end{figure}
\end{column}
{\color{Blue}\vrule width 1.5pt}
\begin{column}[T]{0.33\textwidth}
\begin{figure}[!htb]
\centering
\caption{Exemplo de legenda de figura.}
\label{fig:graficoxy3}
\includegraphics[width = 0.75\columnwidth]{./Figuras/graficoxy}
\source{Autoria própria.}
\end{figure}
\end{column}
\end{block}

\end{column}

\end{columns}

\begin{columns}[t]

\begin{column}{0.45\textwidth}

\begin{block}{Conclusion}
\begin{itemize}
\item Conclusão 1.
\item Conclusão 2.
\item Conclusão 3.
\item Conclusão 4.
\item Conclusão 5.
\end{itemize}
\end{block}

%\begin{block}{AGRADECIMENTOS}
%\vspace*{10px}%
%
%\includegraphics[height = 30mm]{./Logos/logo-capes}
\hspace*{5mm}
%\includegraphics[height = 30mm]{./Logos/logo-cnpq}
\hspace*{5mm}
%\includegraphics[height = 30mm]{./Logos/logo-fa}
\hspace*{5mm}
%\includegraphics[height = 30mm]{./Logos/logo-utfpr}
%\end{block}

\end{column}

\begin{column}{0.45\textwidth}

\begin{block}{References}
%\bibliography{bib}
\printbibliography[heading = none]
\end{block}

\end{column}

\end{columns}

\begin{columns}[t]

\begin{column}{0.945\textwidth}
\vfill%
\end{column}

\end{columns}
\vfill
\footnotesize
\bf{ICRA 2019: The second International Conference on Radiations and Applications}%
\end{frame}
%% Fim do documento
\end{document}

and here is the second file (utfprpgtex-poster):

%% Identificação e modificações
\NeedsTeXFormat{LaTeX2e}[2005/12/01]
\ProvidesPackage{utfprpgtex-poster}[2018/09/28 v1.0 utfprpgtex-poster package]
%% -- Criação dos arquivos constituintes deste projeto.

%% Pacotes utilizados
\RequirePackage[utf8]{inputenc}
\RequirePackage[T1]{fontenc}
\RequirePackage{babel}
\RequirePackage{lmodern}
% \RequirePackage{mathptmx}
% \RequirePackage{helvet}
\RequirePackage{amsmath}
\RequirePackage{amssymb}
\RequirePackage{icomma}
\RequirePackage{csquotes}
\RequirePackage{xpatch}
\RequirePackage[%
  style = chem-angew,%
  natbib = true,%
  uniquename = init,%
  giveninits,%
  backend = biber%
]{biblatex}
\RequirePackage{beamerposter}

%% Definições de cores
\definecolor{BlackBlue}{RGB}{0, 0, 85}
\definecolor{UTFPRBlack}{RGB}{55, 52, 53}
\definecolor{UTFPRYellow}{RGB}{254, 203, 41}
\definecolor{Blue}{RGB}{52, 84, 180}
\definecolor{White}{RGB}{255, 255, 255}


%% Variáveis dependentes do idioma
\iflanguage{english}{%
  \newcommand*{\sourcename}{Source}%
  \IfFileExists{english-abnt.lbx}{%
    \typeout{biblatex-abnt warning: using default language file `english-abnt.lbx'}%
  }{%
    \typeout{biblatex-abnt warning: using local language file `abnt-english.lbx'}%
    \DeclareLanguageMapping{english}{abnt-english}%
  }%
}{%
 % \newcommand*{\utfprname}{Universidade Tecnológica Federal do Paraná}%
  \newcommand*{\sourcename}{Fonte}%
}

%% Definições de comandos
\newcommand*{\email}[2][]{\inst{#1}\href{mailto:#2}{#2}}
\newcommand*{\source}[1]{\par\small\sourcename:\space#1}
\newcommand*{\sep}{,\space}
\renewcommand*{\And}{\sep}

%% Customizações da classe beamer
\mode<presentation>{%
  \usetheme{Pittsburgh}%
  \usefonttheme[onlymath]{serif}%
  %\usebackgroundtemplate{\includegraphics[width = \paperwidth, height = \paperheight]{./Logos/fundo-utfpr}}%
  \setbeamercolor*{title}{fg = black}%
  \setbeamercolor*{title page}{fg = black}%
  \setbeamercolor*{block title}{fg = White, bg = Blue}%
  \setbeamercolor*{structure}{fg = Blue}%
  \setbeamercolor*{caption name}{fg = black}%
  \setbeamercolor*{bibliography entry author}{fg = black}%
  \setbeamercolor*{bibliography entry title}{fg = black}%
  \setbeamercolor*{bibliography entry location}{fg = black}%
  \setbeamercolor*{bibliography entry note}{fg = black}%
  \setbeamerfont{title}{series = \bfseries}%
  \setbeamerfont{institute}{size = \small}%
  \setbeamertemplate{caption}[numbered]%
  \setbeamertemplate{caption label separator}[endash]%
  \setbeamertemplate{bibliography item}{\scalebox{1.5}{\pgfuseimage{beamericonarticle}}}%
}

%% Configurações do pacote lmodern
\@ifpackageloaded{lmodern}{%
  \DeclareFontFamily{OMX}{lmex}{}%
  \DeclareFontShape{OMX}{lmex}{m}{n}{<->lmex10}{}%
}{}

%% Configurações do pacote biblatex
\setlength{\biblabelsep}{\labelsep}
\setlength{\bibitemsep}{\itemsep}
\defbibenvironment{bibliography}{%
  \list{\printfield[labelalphawidth]{labelalpha}}{%
    % \setlength{\labelwidth}{\labelalphawidth}%
    \setlength{\leftmargin}{\labelwidth}%
    \setlength{\labelsep}{\biblabelsep}%
    \addtolength{\leftmargin}{\labelsep}%
    \setlength{\itemsep}{\bibitemsep}%
    \setlength{\parsep}{\bibparsep}%
  }%
  \renewcommand*{\makelabel}[1]{\hss##1}%
}{\endlist}{\item}

%% Configurações do pacote hyperref
\hypersetup{%
  breaklinks = true,%
  colorlinks = true,%
  citecolor = BlackBlue,%
  filecolor = BlackBlue,%
  linkcolor = BlackBlue,%
  urlcolor = BlackBlue,%
  pdfdisplaydoctitle = true,%
  pdfpagelayout = SinglePage,%
}

%% Configurações do pacote url
\g@addto@macro{\UrlBreaks}{\UrlOrds}

%% Equações
\renewcommand*{\normalfont}{\relax}

%% Supressão do aviso para notas de rodapé
\RequirePackage{silence}
\WarningFilter{biblatex}{Patching footnotes failed}

and the bibliography file (bib):

% Encoding: UTF-8

@PhdThesis{yekken2009thesis,
  author = {R. Yekken},
  title  = {Du spectre au potentiel {\'e}tude du probl{\`e}me inverse dans le cas des {\'e}tats discrets avec extension aux potentiels d{\'e}pendant de l'{\'e}nergie},
  school = {Universit{\'e} des sciences et de la technologie Houari Boumediene},
  year   = {2009},
}
@Article{yekken2010energy,
  author    = {R. Yekken and R. J. Lombard},
  title     = {Energy-dependent potentials and the problem of the equivalent local potential},
  journal   = {Journal of Physics A: Mathematical and Theoretical},
  year      = {2010},
  volume    = {43},
  number    = {12},
  pages     = {125301},
  month     = {mar},
  doi       = {10.1088/1751-8113/43/12/125301},
  publisher = {{IOP} Publishing},
  url       = {https://doi.org/10.1088%2F1751-8113%2F43%2F12%2F125301},
}

@Article{yekken2013applying,
  author   = {R. Yekken and M. Lassaut and R. J. Lombard},
  title    = {Applying supersymmetry to energy dependent potentials},
  journal  = {Annals of Physics},
  year     = {2013},
  volume   = {338},
  pages    = {195 - 206},
  issn     = {0003-4916},
  doi      = {https://doi.org/10.1016/j.aop.2013.08.005},
  keywords = {Supersymmetry, Energy dependent potentials},
  url      = {http://www.sciencedirect.com/science/article/pii/S0003491613001747},
}

@Article{yekken2013bound,
  author   = {R. Yekken and M. Lassaut and R. J. Lombard},
  title    = {Bound States of Energy Dependent Singular Potentials},
  journal  = {Few-Body Systems},
  year     = {2013},
  volume   = {54},
  number   = {11},
  pages    = {2113--2124},
  month    = {Nov},
  issn     = {1432-5411},
  day      = {01},
  doi      = {10.1007/s00601-013-0720-3},
  url      = {https://doi.org/10.1007/s00601-013-0720-3},
}



@Article{formanek2004wave,
  author   = {J. Form{\'a}nek and R. J. Lombard and J. Mare{\v{s}}},
  title    = {Wave equations with energy-dependent potentials},
  journal  = {Czechoslovak Journal of Physics},
  year     = {2004},
  volume   = {54},
  number   = {3},
  pages    = {289--315},
  month    = {Mar},
  issn     = {1572-9486},
  day      = {01},
  doi      = {10.1023/B:CJOP.0000018127.95600.a3},
  url      = {https://doi.org/10.1023/B:CJOP.0000018127.95600.a3},
}
@Article{lombard2007wave,
  author    = {R. J. Lombard and J. Mare{\v{s}} and C. Volpe},
  title     = {Wave equation with energy-dependent potentials for confined systems},
  journal   = {Journal of Physics G: Nuclear and Particle Physics},
  year      = {2007},
  volume    = {34},
  number    = {9},
  pages     = {1879--1889},
  month     = {jul},
  doi       = {10.1088/0954-3899/34/9/002},
  publisher = {{IOP} Publishing},
  url       = {https://doi.org/10.1088%2F0954-3899%2F34%2F9%2F002},
}

@Article{lombard2009many,
  author   = {R. J. Lombard and J. Mareš},
  title    = {The many-body problem with an energy-dependent confining potential},
  journal  = {Physics Letters A},
  year     = {2009},
  volume   = {373},
  number   = {4},
  pages    = {426 - 429},
  issn     = {0375-9601},
  doi      = {https://doi.org/10.1016/j.physleta.2008.12.009},
  url      = {http://www.sciencedirect.com/science/article/pii/S0375960108017209},
}

@Comment{jabref-meta: databaseType:biblatex;}

As you can seen in the image, there is no numbers on the left of the references.

Answer 1

The

\setbeamertemplate{bibliography item}{\scalebox{1.5}{\pgfuseimage{beamericonarticle}}}

in utfprpgtex-poster.sty explicitly disables the numbering in the bibliography and forces the little icons to be shown instead (though to be fair, it is already the beamer default to place the little icons, this line does not make things worse in that regard, it just scales the icon a bit). How do I get numbered entries in a beamer bibliography explains that you can get back the citation labels with

\setbeamertemplate{bibliography item}{\insertbiblabel}

Unfortunately, that alone does not work, because utfprpgtex-poster.sty also redefines the bibliography environment in a way that is basically incompatible with numeric styles. The definition reads

\defbibenvironment{bibliography}{%
  \list{\printfield[labelalphawidth]{labelalpha}}{%
    % \setlength{\labelwidth}{\labelalphawidth}%
    \setlength{\leftmargin}{\labelwidth}%
    \setlength{\labelsep}{\biblabelsep}%
    \addtolength{\leftmargin}{\labelsep}%
    \setlength{\itemsep}{\bibitemsep}%
    \setlength{\parsep}{\bibparsep}%
  }%
  \renewcommand*{\makelabel}[1]{\hss##1}%
}{\endlist}{\item}

and is only suitable for aphabetic styles (but compare the proper definition in alphabetic.bbx, the fields labelprefix and extraalpha should be printed as well; so the definition is flawed even for alphabetic styles). You want to get rid of this block of code completely.

---

If you modify the .sty file directly, please rename it and place a short notice of the changes along with proper version and date information on the top of the modified file. Do not change the .sty file without renaming it.

If you don't want to change the .sty you can overwrite the unwanted code in your document preamble by adding

\setbeamertemplate{bibliography item}{\insertbiblabel}

and the correct bibliography definition for a numeric style

\defbibenvironment{bibliography}
  {\list
     {\printtext[labelnumberwidth]{%
        \printfield{labelprefix}%
        \printfield{labelnumber}}}
     {\setlength{\labelwidth}{\labelnumberwidth}%
      \setlength{\leftmargin}{\labelwidth}%
      \setlength{\labelsep}{\biblabelsep}%
      \addtolength{\leftmargin}{\labelsep}%
      \setlength{\itemsep}{\bibitemsep}%
      \setlength{\parsep}{\bibparsep}}%
      \renewcommand*{\makelabel}[1]{\hss##1}}
  {\endlist}
  {\item}

Having to add the bibliography environment again is a bit unfortunate, but the .sty has overwritten the correct definition.

---

In general I would advise against using random templates you find on Overleaf. You can never be sure if they can be changed to fit your needs and they are often not properly maintained or supported.