duplicate citation number in front of bibliography entry IEEE style

I get the following in my bibliography (in word 2007).
How to remove one of the duplicate leading numbers?
I'm using zotero 2.1.5 and zotero word integration 3.1, the citation style is based on IEEE, which share the same problem

[1] [1] Weiser M. The computer for the 21 century [J]. Scientific American, 1991, 265(3): 94–104.
[2] [2] Satyanarayanan M. Pervasive computing: Vision and challenges [J]. IEEE Personal Communications, 2001, 8(4): 10–17.
[3] [3] Gal CL, Martin J, Lux A, Crowley JL. Smart Office: Design of an Intelligent Environment [J]. IEEE Intelligent Systems, 2001, 16(4): 60-66.
[4] [4] Cook DJ, Youngblood M, Heierman III EO, Gopalratnam K, Rao S, Litvin A, Khawaja F. MavHome: An agent-based smart home [C]// Proceedings of the First IEEE International Conference on Pervasive Computing and Communications, 2003.(PerCom 2003). 2003. 521–524.

This is an old discussion that has not been active in a long time. Instead of commenting here, you should start a new discussion. If you think the content of this discussion is still relevant, you can link to it from your new discussion.