How colud i found exhibitiors??? For International Exhibition

I have just changed  a job,and now i am doing for International Fair,organize a group of company go to abroad  of China to participate the Exhibition.

I tried to found some contact details on line,and give them a call,sending a fax,and Email,but it seems do not work....???

Is there anyone have any good idea??? :)

I am really appreciate if you can tell me about it. Thanks!