Error generating section title references when using amsmath package

Question

I am preparing a work and for this I need to use keys in the equations mode as following:

\begin{equation}
\Delta \eta_{i,j} = 
   \begin{cases}
     \eta_{i,j},&  se\quad aresta\quad i,j\quad foi\quad utilizada \\
      0,        &  se\quad aresta\quad i,j\quad n\tilde{a}o\quad foi\quad utilizada
   \end{cases}
\label{eq5}
\end{equation}

For this I need to use the

\usepackage{amsmath}

However, when I use this package (I have already run the test including and removing it, it is it that generates the error) in the command call

\bibliography{referencias}

to generate my references the section title goes wrong. That way

7  *
    Referências

No formatting at all. It was not to be numbered including this section.

Can someone help me? I don’t know what’s going on.

Answer 1

Function definition is correct (and works perfectly) (check only if the \usepackage{...} is in the preamble (i.e. before the \begin{document})

---

the issue of bibiography is something completely different

\bibliography{referencias} indicates that you have an external file (referencias.bib) containing bibliographic references.

This can give errors in several situations. Example:

• the file does not exist;
• exist but not be in the right syntax,
• there is no bibliographical citation ( \cite{chave}),
• or if you use keyquotes that are not defined.

If this is the case: correct the respective errors or comment or withdraw the \bibliography{referencias}