EXHIBIT 4.4 GRANT OF REGISTRATION RIGHTS TO US BIOSERVICES CORPORATION STOCKHOLDERS The undersigned, in accordance with an Agreement and Plan of Merger, dated as of the date hereof (the "Merger Agreement"), entered into by and among AmerisourceBergen...Grant of Registration Rights • December 20th, 2002 • Amerisourcebergen Corp • Wholesale-drugs, proprietaries & druggists' sundries
