References

BHP Billiton Petroleum (Americas)  Inc.
1360 Post Oak Blvd, Suite 150
Houston, TX 77056

Phone: (713) 961-8500
Contact: Mr. David Powell, Chief Financial Officer

EOG Resources Company
1111 Bagby, Sky Lobby 2
Houston, TX 77002

Phone: (713) 651-6622
Contact: Mr. Kevin Hanzel, Vice President - Internal Audit

Occidental Petroleum Corporation
5 Greenway Plaza, Suite 110
Houston, Texas 77046

Phone: (713) 215-7000
Contact: Mr. Gary Daugherty, Vice President – Internal Audit