diff --git a/API-Reference.md b/API-Reference.md
index 6d9dae1..f4d772a 100644
--- a/API-Reference.md
+++ b/API-Reference.md
@@ -27,4 +27,9 @@ The following functions are provided by the library:
 |s.rand(min=0, max=1)|Random float|
 |s.randi(min=0, max=1)|Random integer|
 
+## Sounds and music
 
+|Function|Description|
+|---|---|
+|s.sfx(ZzFXParams, pitchSlide, volume)|Play a [ZzFX](https://killedbyapixel.github.io/ZzFX/) sound effect|
+|s.volume(volume)|Change the volume|