Cancer causing viruses

[L. Do]

I'm a student studying microbiology.  Specifically, I am interested in 
viral oncology. It would be greatly appreciated if anyone who has 
knowledge in this area could post information on (1) viruses that 
directly cause cancer; and (2) viruses that may trigger cancer. Even if 
you don't have time to post information. Any notes on good research 
sources in this area would be a huge help. Thank you in advance.
			-Ly
			(University of Iowa)