diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 8cad8b9d..9c0aa827 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -15,6 +15,7 @@ Before starting, you need a few tools.
   -  `arcansit`
   - `python3-sphinx`
   - `texlive`
+  - `texlive-formats-extra`
  - The following packages from PyPI:
   - `sphinx_bootstrap_theme`