diff --git a/content/tips/latex-letterhead.md b/content/tips/latex-letterhead.md
index 1c13f0c..1da23d6 100644
--- a/content/tips/latex-letterhead.md
+++ b/content/tips/latex-letterhead.md
@@ -15,7 +15,7 @@ Especially, I feel more comfortable editing some LaTeX instead of writing it in
 Thus, thanks to [Nicolas Trotignon](https://perso.ens-lyon.fr/nicolas.trotignon/) who found a simple workaround, here is a small trick to do it.
 As a preliminary, you have to obtain a pdf version of the letterhead (to do so, I'm using [online office 365](https://en.wikipedia.org/wiki/Office_365) as it works in Linux, yes, shame on me).
 
-Once this is done, the core of this method is to use the `wallpaper` package to embed the letterhead as a background image, and then play with margins to make it look nice.
+Once this is done, the core of this method is to use the [wallpaper](https://www.ctan.org/pkg/wallpaper) package to embed the letterhead as a background image, and then play with margins to make it look nice.
 
 Here follows a minimal example with the [corresponding output](examples/background-latex.pdf). Replace `background.pdf` with your (empty) letterhead of course.
 This can also be adapted to other classes, such as [`letter.cls`](https://ctan.org/pkg/letter).