diff --git a/packages/openapi-types/index.ts b/packages/openapi-types/index.ts
index 5bd58b2b..48b34d4b 100644
--- a/packages/openapi-types/index.ts
+++ b/packages/openapi-types/index.ts
@@ -365,11 +365,32 @@ export namespace OpenAPIV3 {
     url: string;
   }
 
-  export interface ParameterObject extends ParameterBaseObject {
+  export type ParameterObject = PathLocationObject | QueryLocationObject | CookieLocationObject | HeaderLocationObject; 
+
+  export interface CookieLocationObject extends ParameterBaseObject {
     name: string;
-    in: string;
+    in: "cookie";
+    style?: "form";
+  }
+    
+  interface HeaderLocationObject extends ParameterBaseObject {
+    name: string;
+    in: "header";
+    style?: "simple";
+  }
+    
+  interface PathLocationObject extends ParameterBaseObject {
+    name: string;
+    in: "path";
+    required: boolean;
+    style?: "matrix" | "label" | "simple";
+  }
+    
+  interface QueryLocationObject extends ParameterBaseObject {
+    name: string;
+    in: "query";
+    style?: "form" | "spaceDelimited" | "pipeDelimited" | "deepObject";
   }
-
   export interface HeaderObject extends ParameterBaseObject {}
 
   export interface ParameterBaseObject {