diff --git a/777077169fce2ffba439b0af82e0f574/description b/777077169fce2ffba439b0af82e0f574/description
index 186f7d2..b5f019d 100644
--- a/777077169fce2ffba439b0af82e0f574/description
+++ b/777077169fce2ffba439b0af82e0f574/description
@@ -35,3 +35,7 @@ LM386/SC8002B amplifier
 * store audio in MCU flash memory
 * 10 audio files with total of 3-5 seconds of audio time
 * output using PWM channels, will filter in HW
+
+
+# REFERENCE
+[spec](https://docs.google.com/document/d/1WP9aMegpzNuwF81Cxm263mibuAER9fZ7Ktj7NuHr9Rs)