diff --git a/README.md b/README.md
index 832aac7..19686da 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,7 @@ package for Elixir language.
 ## API
 
 The method names and arities/args are stable now. No change should be expected
-on the package for the version `2.x.x` except any bug fixes.
+on the package for the version `3.x.x` except any bug fixes.
 
 ## Installation
 
diff --git a/bus.go b/bus.go
index adb2fd0..47daac0 100644
--- a/bus.go
+++ b/bus.go
@@ -50,6 +50,7 @@ type (
 		Matcher string
 	}
 
+	// EventOption is a function type to mutate event fields
 	EventOption = func(Event) Event
 
 	ctxKey int8
@@ -105,7 +106,7 @@ func WithSource(source string) EventOption {
 	}
 }
 
-// WithSource returns an option to set event's occurredAt field
+// WithOccurredAt returns an option to set event's occurredAt field
 func WithOccurredAt(time time.Time) EventOption {
 	return func(e Event) Event {
 		e.OccurredAt = time