diff --git a/knowledge base/apt.md b/knowledge base/apt.md
index c542ba4..ffc2991 100644
--- a/knowledge base/apt.md	
+++ b/knowledge base/apt.md	
@@ -91,7 +91,8 @@ sudo apt update
 - [Configuring Apt sources]
 - [Unattended Upgrades]
 - [`dpkg`][dpkg]
-- [`apt-file`][apt-file]
+- [`apt-file`][apt-file] to look for files in packages
+- [`netselect-apt`][netselect-apt] to select the fastest APT mirror
 
 ## Sources
 
@@ -106,6 +107,7 @@ sudo apt update
 <!-- internal references -->
 [apt-file]: apt-file.md
 [dpkg]: dpkg.md
+[netselect-apt]: netselect-apt.md
 
 <!-- external references -->
 [cheat.sh]: https://cheat.sh/apt
diff --git a/knowledge base/netselect-apt.md b/knowledge base/netselect-apt.md
new file mode 100644
index 0000000..29d13de
--- /dev/null
+++ b/knowledge base/netselect-apt.md	
@@ -0,0 +1,44 @@
+# `netselect-apt`
+
+Creates `sources.list` files for the fastest Debian mirrors.
+
+It:
+
+1. downloads the list of Debian mirrors from <http://www.debian.org/mirror/mirrors_full> using `wget`;
+1. chooses the fastest servers using `netselect`;
+1. tests the valid servers using `curl` if available.
+
+The output file is written to OUTFILE.
+
+## Table of contents <!-- omit in toc -->
+
+1. [TL:DR](#tldr)
+1. [Further readings](#further-readings)
+1. [Sources](#sources)
+
+## TL:DR
+
+```sh
+sudo netselect-apt --arch 'amd64' --country 'de' --outfile '/tmp/sources.list'
+sudo netselect-apt --nonfree
+sudo netselect-apt -nc 'nl'
+```
+
+## Further readings
+
+- [`man` page][man page]
+
+## Sources
+
+All the references in the [further readings] section, plus the following:
+
+- [How to find the fastest mirror in Debian and derivatives]
+
+<!-- project's references -->
+[man page]: https://manpages.debian.org/testing/netselect-apt/netselect-apt.1.en.html
+
+<!-- internal references -->
+[further readings]: #further-readings
+
+<!-- external references -->
+[how to find the fastest mirror in debian and derivatives]: https://www.unixmen.com/find-fastest-mirror-debian-derivatives/