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Most of these are on the re-issues of Deep Purple, Shades of Deep Purple, The Book of Taliesyn as bonus tracks. Most of the remaining tracks could be from Deep Purple In Concert or Scandinavian Nights, both of which are also officially.
The title is a misnomer - few if any of the tracks are actually from 1971. The first three feature Mk I, and the rest Mk II, including a rare Mk II version of Bird Has Flown and many In Rock numbers rarely played live.