It's interesting to see or discover that such iconics songs' from Led Zeppelin have been credited or thought of being written by Page/Plant, here's some interesting links:
Nobody's Fault But Mine: http://www.youtube.com/watch?v=QZLyGk875EY&ob=av2n
, Led Zep version is a cover :)
Is the intro of Stairway to Heaven by Jimmy Page? http://www.youtube.com/watch?v=xd8AVbwB_6E
, the similarities are uncanny and it was certainly released before Led Zep... thoughts?