diff --git a/scrapling/core/_types.py b/scrapling/core/_types.py
index c897954..48a2eec 100644
--- a/scrapling/core/_types.py
+++ b/scrapling/core/_types.py
@@ -19,6 +19,7 @@ from typing import (
     Set,
     Literal,
     Optional,
+    Iterator,
     Pattern,
     Sequence,
     Tuple,
diff --git a/scrapling/engines/_browsers/_controllers.py b/scrapling/engines/_browsers/_controllers.py
index 285bb32..aef197a 100644
--- a/scrapling/engines/_browsers/_controllers.py
+++ b/scrapling/engines/_browsers/_controllers.py
@@ -108,8 +108,11 @@ class DynamicSession(SyncSession, DynamicSessionMixin):
         if not self._is_alive:  # pragma: no cover
             raise RuntimeError("Context manager has been closed")
 
+        request_headers_keys = {h.lower() for h in params.extra_headers.keys()} if params.extra_headers else set()
         referer = (
-            generate_convincing_referer(url) if (params.google_search and "referer" not in self._headers_keys) else None
+            generate_convincing_referer(url)
+            if (params.google_search and "referer" not in request_headers_keys)
+            else None
         )
 
         page_info = self._get_page(params.timeout, params.extra_headers, params.disable_resources)
@@ -240,8 +243,11 @@ class AsyncDynamicSession(AsyncSession, DynamicSessionMixin):
         if not self._is_alive:  # pragma: no cover
             raise RuntimeError("Context manager has been closed")
 
+        request_headers_keys = {h.lower() for h in params.extra_headers.keys()} if params.extra_headers else set()
         referer = (
-            generate_convincing_referer(url) if (params.google_search and "referer" not in self._headers_keys) else None
+            generate_convincing_referer(url)
+            if (params.google_search and "referer" not in request_headers_keys)
+            else None
         )
 
         page_info = await self._get_page(params.timeout, params.extra_headers, params.disable_resources)
diff --git a/scrapling/engines/_browsers/_stealth.py b/scrapling/engines/_browsers/_stealth.py
index e191059..6883fdf 100644
--- a/scrapling/engines/_browsers/_stealth.py
+++ b/scrapling/engines/_browsers/_stealth.py
@@ -195,8 +195,11 @@ class StealthySession(SyncSession, StealthySessionMixin):
         if not self._is_alive:  # pragma: no cover
             raise RuntimeError("Context manager has been closed")
 
+        request_headers_keys = {h.lower() for h in params.extra_headers.keys()} if params.extra_headers else set()
         referer = (
-            generate_convincing_referer(url) if (params.google_search and "referer" not in self._headers_keys) else None
+            generate_convincing_referer(url)
+            if (params.google_search and "referer" not in request_headers_keys)
+            else None
         )
 
         page_info = self._get_page(params.timeout, params.extra_headers, params.disable_resources)
@@ -410,8 +413,11 @@ class AsyncStealthySession(AsyncSession, StealthySessionMixin):
         if not self._is_alive:  # pragma: no cover
             raise RuntimeError("Context manager has been closed")
 
+        request_headers_keys = {h.lower() for h in params.extra_headers.keys()} if params.extra_headers else set()
         referer = (
-            generate_convincing_referer(url) if (params.google_search and "referer" not in self._headers_keys) else None
+            generate_convincing_referer(url)
+            if (params.google_search and "referer" not in request_headers_keys)
+            else None
         )
 
         page_info = await self._get_page(params.timeout, params.extra_headers, params.disable_resources)