Remove # from References using knitcitations package

I need to remove # symbol from my Rmarkdown document, specific at References section. I use an external .bib archive called biblio.bib.

My YAML header is:

---
output: 
    pdf_document:
      number_sections: true
header-includes:
  - \usepackage[spanish]{babel}     
  - \usepackage{cite}
bibliography: biblio.bib
---

and at References section I use knitcitations package:

# Referencias {-}




```{r generateBibliography, echo=FALSE, eval=TRUE, message=FALSE, warning=FALSE}
require("knitcitations")
cleanbib()
read.bibtex(file = "biblio.bib")
```

My pdf_document output: