↑ ""Unocal World On-Line."". Archived from the original on December 27, 1996. Dicapai 2009-07-07. Selenggaraan CS1: BOT: Status original-url tidak diketahui (link) Unocal Corporation. December 27, 1996. Retrieved on July 7, 2009.
↑ "Home page". Archived from the original on January 29, 2005. Dicapai 2009-07-07. Selenggaraan CS1: BOT: Status original-url tidak diketahui (link) . Unocal Corporation. January 29, 2005. Retrieved on July 7, 2009.
