diff --git a/build.gradle b/build.gradle
index dbcc203f..6112a23e 100644
--- a/build.gradle
+++ b/build.gradle
@@ -6,6 +6,8 @@ buildscript {
     }
     dependencies {
         // http://tools.android.com/tech-docs/new-build-system/gradle-experimental
+        // https://bintray.com/android/android-tools/com.android.tools.build.gradle-experimental/view
+        // https://bintray.com/android/android-tools/com.google.gms.google-services/view
         classpath 'com.android.tools.build:gradle-experimental:0.9.3'
         classpath 'com.google.gms:google-services:3.1.0'