diff --git a/karaokatalog/Song.py b/karaokatalog/Song.py
index 31caed2..db207d4 100644
--- a/karaokatalog/Song.py
+++ b/karaokatalog/Song.py
@@ -6,6 +6,9 @@ import filecmp
 
 from dataclasses import dataclass
 
+type Title = str
+type Artist = str
+
 
 @dataclass(frozen=True)
 class Song:
@@ -15,8 +18,8 @@ class Song:
     See https://usdx.eu/format/ for the specification.
     """
 
-    title: str
-    artist: str
+    title: Title
+    artist: Artist
     audio: Path | None
     video: Path | None
     cover: Path | None