Basic knife fighting resource

Hey guys,

I have pretty much no idea what basic principles there are in fighting with a knife or against a knife. What are the best ones?

The only experience i have with MA or self defense is 18 hours of PPCT training. I like PPCT because it seems like a simple collection of moves that work effectively and are easy to train someone with. Is there an equivalent for knife fighting?

Any comments or advice?

thanks