Questionmark in bibliography

Hello,

I've one or two books in my bibliography that have a questionmark in their titles. E.g. one title is "Is it  
an Agent, or just a Program?"

In the output for print this results in something like
	[abbrev] Names of authors. Is it an Agent, or just a Program?. publisher

Well, I would like to get rid of the '.' after the '?'. Is that possible?


best regards
Steffen