EXHIBIT 3.20



                            CERTIFICATE OF FORMATION

                                       OF

                               BI ACQUISITION, LLC


     This Certificate of Formation of BI Acquisition, LLC (the "LLC") has been
duly executed and is being filed by the undersigned, as an authorized person, to
form a limited liability company under the Delaware Limited Liability Act (6
Del. C. (S) 18-101, et. seq.).
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     FIRST. The name of the limited liability company formed hereby is BI
Acquisition, LLC.

     SECOND. The address of the registered office of the LLC in the State of
Delaware is c/o Corporation Service Company, 1013 Centre Road, Wilmington, New
Castle County, Delaware 19805.

     THIRD. The name and address of the registered agent for service of process
on the LLC in the State of Delaware is Corporation Service Company, 1013 Centre
Road, Wilmington, New Castle County, Delaware 19805.

     IN WITNESS WHEREOF, the undersigned has duly executed this Certificate of
Formation as of this 22nd day of July, 1999.


                                                     /s/ Thomas J. Moratti
                                                     --------------------------
                                                     Thomas J. Moratti
                                                     Authorized Person