The "look ahead" decision algorithm in DFE

Hi,
Im currently try to implement a DFE equalizer. When I read on this
subject, I see that a special decision algorithm, called "look ahead" is
performed in order to reduce the effect of error propagation.
Unfortunately, I could not find any informative article about this issue.
Can you explain it to me the principle of it? Does it a variation of
viterby algorithm (a sequence detector)? 
Thanks,
Moshe