Commission Regulation (EC) No 1646/1999 of 27 July 1999 initiating an investigation concerning the alleged circumvention of anti-dumping measures imposed by Council Regulation (EC) No 2861/93 on imports of certain magnetic disks (3,5 in. microdisks) originating in Taiwan and the People's Republic of China by assembly operations in the Community and making imports of microdisk parts subject to registration