diff --git a/Source/Core/OrthographicFrustum.js b/Source/Core/OrthographicFrustum.js
index 5f3cd11f07c2..be0a941eb616 100644
--- a/Source/Core/OrthographicFrustum.js
+++ b/Source/Core/OrthographicFrustum.js
@@ -3,6 +3,7 @@ import Check from './Check.js';
 import defaultValue from './defaultValue.js';
 import defined from './defined.js';
 import defineProperties from './defineProperties.js';
+import deprecationWarning from './deprecationWarning.js';
 import DeveloperError from './DeveloperError.js';
 import CesiumMath from './Math.js';
 import OrthographicOffCenterFrustum from './OrthographicOffCenterFrustum.js';
diff --git a/Source/Core/OrthographicOffCenterFrustum.js b/Source/Core/OrthographicOffCenterFrustum.js
index 88b09b60df56..96d2eca200c0 100644
--- a/Source/Core/OrthographicOffCenterFrustum.js
+++ b/Source/Core/OrthographicOffCenterFrustum.js
@@ -5,6 +5,7 @@ import CullingVolume from './CullingVolume.js';
 import defaultValue from './defaultValue.js';
 import defined from './defined.js';
 import defineProperties from './defineProperties.js';
+import deprecationWarning from './deprecationWarning.js';
 import DeveloperError from './DeveloperError.js';
 import CesiumMath from './Math.js';
 import Matrix4 from './Matrix4.js';
diff --git a/Source/Core/PerspectiveFrustum.js b/Source/Core/PerspectiveFrustum.js
index 4f76eb286326..f16f8e34496b 100644
--- a/Source/Core/PerspectiveFrustum.js
+++ b/Source/Core/PerspectiveFrustum.js
@@ -3,6 +3,7 @@ import Check from './Check.js';
 import defaultValue from './defaultValue.js';
 import defined from './defined.js';
 import defineProperties from './defineProperties.js';
+import deprecationWarning from './deprecationWarning.js';
 import DeveloperError from './DeveloperError.js';
 import CesiumMath from './Math.js';
 import PerspectiveOffCenterFrustum from './PerspectiveOffCenterFrustum.js';
diff --git a/Source/Core/PerspectiveOffCenterFrustum.js b/Source/Core/PerspectiveOffCenterFrustum.js
index 5c9cfd35f08d..7e716bc8cc83 100644
--- a/Source/Core/PerspectiveOffCenterFrustum.js
+++ b/Source/Core/PerspectiveOffCenterFrustum.js
@@ -5,6 +5,7 @@ import CullingVolume from './CullingVolume.js';
 import defaultValue from './defaultValue.js';
 import defined from './defined.js';
 import defineProperties from './defineProperties.js';
+import deprecationWarning from './deprecationWarning.js';
 import DeveloperError from './DeveloperError.js';
 import CesiumMath from './Math.js';
 import Matrix4 from './Matrix4.js';