diff --git a/bigquery/README.md b/bigquery/README.md
index 47a64699866..28c61c47eb8 100644
--- a/bigquery/README.md
+++ b/bigquery/README.md
@@ -36,7 +36,7 @@ if err != nil {
 for {
 	var values []bigquery.Value
 	err := it.Next(&values)
-	if err == iterator.Done {
+	if err == iterator.Done {  // from "google.golang.org/api/iterator"
 		break
 	}
 	if err != nil {
@@ -44,4 +44,4 @@ for {
 	}
 	fmt.Println(values)
 }
-```
\ No newline at end of file
+```