(美)Dean Leffingwell著 Dean Leffingwell. Randy Leffingwell (美)Dean MacCannell著 Randy Leffingwell. (美)迪恩·莱芬韦尔(Dean Leffingwell)等著 (美)Ryan Mitchell著 (美)Jenifer Tidwell著 (美)兰迪·莱芬韦尔(Randy Leffingwell)著 By Randy Leffingwell