diff --git a/include/yamerl_types.hrl b/include/yamerl_types.hrl
index 8ba56b7..a613065 100644
--- a/include/yamerl_types.hrl
+++ b/include/yamerl_types.hrl
@@ -40,7 +40,8 @@
 -type encoding()         :: utf8
                           | {utf16, little | big}
                           | {utf32, little | big}.
--type unicode_string()   :: [unicode:unicode_char()].
+-type unicode_char()     :: integer().
+-type unicode_string()   :: [unicode_char()].
 %% unicode:external_unicode_binary() (UTF16/32) not exported.
 -type unicode_binary()   :: unicode:unicode_binary().
 -type unicode_data()     :: unicode_string()