References do not show using RMarkdown

[sbac]

I can't print my references in this simple example.

---
title: "test2"
output: pdf_document
bibliography: eng.bib
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = FALSE, warning = FALSE, message = FALSE)
```

# References

This is my eng.bib file:

@Manual{R-base,
  title = {R: A Language and Environment for Statistical
           Computing},
  author = {{R Core Team}},
  organization = {R Foundation for Statistical Computing},
  address = {Vienna, Austria},
  year = {2019},
  url = {https://www.R-project.org},
}

[cderv]

It seems you did not use any reference in the example.

See about several ways to do it, included printing all the references without refering them

4.5 Bibliographies and citations | R Markdown Cookbook

[sbac]

Yes. Of course. I forgot that