[Straight Vermonter]

I'm sure that is true. It is significant, however, to make the connection that the bands mentioned in the article are influenced by a band that was itself influenced and imitating other even earlier musicians.

When I discovered Willie Dixon I couldn't believe how much of his music was borrowed (stolen) by Zep and other bands.

[Fledermaus]

Yeah, most of their first album, like many other artist in the late 60's (including the Beatles in the early 60's) stole lots of music for the old black blues and R&B artist.

[Mr. Blonde]

I remember reading that the writer of Babe, I'm Going to Leave You had no idea Zeppelin had covered it. Many years later she played it for her family and they asked why she was singing a Zep song, and she said no, that was one of hers. I think she was rewarded quite well for the discovery. I think Willie Dixon ended up getting a piece of the pie too.