Tow hooks

I have a 91 XJ sport. just starting to build it up, I have stock bumpers on it I need to know where and how to attach tow hooks. Can they be bolted on or do they have to be welded on.

you have to find the eloborate braces that came on some jeeps stock. they follow the frame rail back about a foot and a half and bolt on in tons of places....they are a bitch to put on because you have to take your steering box off. they are very nessecary if you want to tow your jeep without tearing the frame rails.