Exhibit A JOINT FILING UNDERTAKING
Exhibit A
The undersigned, being duly authorized thereunto, hereby execute this agreement as an exhibit to
this Schedule 13D to evidence the agreement of the below-named parties, in accordance with the
rules promulgated pursuant to the Securities Exchange Act of 1934, to file this Schedule jointly on
behalf of each such party.
Dated: May 11, 2007
| Value Fund Advisors, LLC | ||||
| By: | /s/ Xxxxxxx X. Xxxxxxx | |||
| Boston Avenue Capital, LLC | ||||
| By: | /s/ Xxxxxxx X. Xxxxxxx | |||
| Yorktown Avenue Capital, LLC | ||||
| By: | /s/ Xxxxxxx X. Xxxxxxx | |||
| /s/ Xxxxxxx X. Xxxxxxx | ||||
