diff --git a/module2/01_partitions_raid_lvm_fs/tasks.md b/module2/01_partitions_raid_lvm_fs/tasks.md
index 4bedad6..0b1e102 100644
--- a/module2/01_partitions_raid_lvm_fs/tasks.md
+++ b/module2/01_partitions_raid_lvm_fs/tasks.md
@@ -101,4 +101,5 @@ ZFS и Btrfs обычно называют файловыми системами
 
 # Релевантная литература
 1. Nemeth E. et al. UNIX and Linux system administration handbook. Chapter 5, Chapter 20.
-2. Lukas, Jude. FreeBSD Mastery: ZFS
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+2. Lukas, Jude. FreeBSD Mastery: ZFS
+3. BTRFS documentation. https://btrfs.readthedocs.io/en/latest/
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