diff --git a/cmd/restic/cmd_backup.go b/cmd/restic/cmd_backup.go
index 3f945bc71..a37d3f168 100644
--- a/cmd/restic/cmd_backup.go
+++ b/cmd/restic/cmd_backup.go
@@ -101,7 +101,7 @@ func init() {
 	f.StringArrayVar(&backupOptions.ExcludeFiles, "exclude-file", nil, "read exclude patterns from a `file` (can be specified multiple times)")
 	f.BoolVarP(&backupOptions.ExcludeOtherFS, "one-file-system", "x", false, "exclude other file systems")
 	f.StringArrayVar(&backupOptions.ExcludeIfPresent, "exclude-if-present", nil, "takes filename[:header], exclude contents of directories containing filename (except filename itself) if header of that file is as provided (can be specified multiple times)")
-	f.BoolVar(&backupOptions.ExcludeCaches, "exclude-caches", false, `excludes cache directories that are marked with a CACHEDIR.TAG file`)
+	f.BoolVar(&backupOptions.ExcludeCaches, "exclude-caches", false, `excludes cache directories that are marked with a CACHEDIR.TAG file. See http://bford.info/cachedir/spec.html for the Cache Directory Tagging Standard`)
 	f.BoolVar(&backupOptions.Stdin, "stdin", false, "read backup from stdin")
 	f.StringVar(&backupOptions.StdinFilename, "stdin-filename", "stdin", "file name to use when reading from stdin")
 	f.StringArrayVar(&backupOptions.Tags, "tag", nil, "add a `tag` for the new snapshot (can be specified multiple times)")
diff --git a/doc/man/restic-backup.1 b/doc/man/restic-backup.1
index 7feae2a20..376f89f67 100644
--- a/doc/man/restic-backup.1
+++ b/doc/man/restic-backup.1
@@ -26,7 +26,7 @@ given as the arguments.
 
 .PP
 \fB\-\-exclude\-caches\fP[=false]
-    excludes cache directories that are marked with a CACHEDIR.TAG file
+    excludes cache directories that are marked with a CACHEDIR.TAG file. See http://bford.info/cachedir/spec.html for the Cache Directory Tagging Standard
 
 .PP
 \fB\-\-exclude\-file\fP=[]
diff --git a/doc/manual_rest.rst b/doc/manual_rest.rst
index e904ad581..07b99a79a 100644
--- a/doc/manual_rest.rst
+++ b/doc/manual_rest.rst
@@ -78,7 +78,7 @@ command:
 
     Flags:
       -e, --exclude pattern                  exclude a pattern (can be specified multiple times)
-          --exclude-caches                   excludes cache directories that are marked with a CACHEDIR.TAG file
+          --exclude-caches                   excludes cache directories that are marked with a CACHEDIR.TAG file. See http://bford.info/cachedir/spec.html for the Cache Directory Tagging Standard
           --exclude-file file                read exclude patterns from a file (can be specified multiple times)
           --exclude-if-present stringArray   takes filename[:header], exclude contents of directories containing filename (except filename itself) if header of that file is as provided (can be specified multiple times)
           --files-from string                read the files to backup from file (can be combined with file args/can be specified multiple times)