diff --git a/doc/Astaroth_API_specification_and_user_manual/API_specification_and_user_manual.md b/doc/Astaroth_API_specification_and_user_manual/API_specification_and_user_manual.md
index 45e5930..4ee06dc 100644
--- a/doc/Astaroth_API_specification_and_user_manual/API_specification_and_user_manual.md
+++ b/doc/Astaroth_API_specification_and_user_manual/API_specification_and_user_manual.md
@@ -1,4 +1,4 @@
-a# Astaroth specification and user manual
+# Astaroth specification and user manual
 
 Copyright (C) 2014-2019, Johannes Pekkila, Miikka Vaisala.