It cracks me up when people rip on Led Zeppelin for "stealing" some old blues songs. Tell you what, go to You Tube and actually listen to the originals...if you can. I'll give you about 45 seconds and then you'll turn it off. Know why? Because they're unlistenable and brutally bad. The Led Zeppelin versions are 100% better. Yes, that's no excuse for not giving credit; they absolutely should have.
Yep, Led Zeppelin "ripped off" a few blues tunes and belatedly gave credit. Funny how the same people who love to rip on those particular songs never want to give credit for the rest of the material spread out over 10 albums. Aside from those tracks, all of which is incredibly artistic, genuine and 100% Led Zeppelin awesomeness.