------------------- CUSIP No. 452327109 13 G Page 24 of 25 Pages ------------------- -------------------Venrock Associates • February 14th, 2001 • Laboratory analytical instruments
Pursuant to Rule 13d-1(k)(1) promulgated pursuant to the Securities Exchange Act of 1934, as amended, the undersigned agree that the attached Schedule 13G is being filed on behalf of each of the undersigned.
