Delaware
|
1-9260
|
73-1283193
|
|||
(State
or other jurisdiction
of
incorporation)
|
(Commission
File Number)
|
(I.R.S.
Employer
Identification
No.)
|
7130
South Lewis, Suite 1000, Tulsa, Oklahoma
|
74136
|
||
(Address
of principal executive offices)
|
(Zip
Code)
|
Written
communications pursuant to Rule 425 under the Securities Act (17 CFR
230.425)
|
Soliciting
material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
240.14a-12)
|
Pre-commencement
communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR
240.14d-2(b))
|
Pre-commencement
communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR
240.13e-4(c))
|
(d)
|
Exhibits.
|
Exhibit
No.
|
Description
|
4.1
|
Fourth
Amendment of Rights Agreement dated as of March 24, 2009, between the
Company and American Stock Transfer Company, LLC, as successor to Mellon
Investor Services L.L.C.
|
4.2
|
Standstill
Agreement dated as of March 24, 2009, by and between the Company and the
George Kaiser Family
Foundation
|
Unit
Corporation
|
|
Date:
March 25, 2009
|
By: /s/ Mark E.
Schell
|
Mark
E. Schell
|
|
Senior
Vice President
|
|
and General Counsel |
Description
|
|
4.1
|
Fourth
Amendment of Rights Agreement dated as of March 24, 2009, between the
Company and American Stock Transfer Company, LLC, as successor to Mellon
Investor Services L.L.C.
|
4.2 |
Standstill
Agreement dated as of March 24, 2009, by and between the Company and the
George Kaiser Family
Foundation
|