EXHIBIT 99.1Agreement Regarding Joint Filing Under • February 13th, 2008 • Renaissance Technologies LLC • Instruments for meas & testing of electricity & elec signals
In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, each of the undersigned agrees to the filing on behalf of each of a Statement on Schedule 13G, and all amendments thereto, with respect to the shares of Common Shares, Without Par Value of Keithley Instruments, Inc.
