Cobain's appreciation of early alternative rock bands also extended to Sonic Youth and R.E.M., both of which the members of Nirvana befriended and looked up to for advice. It was under recommendation from Sonic Youth's Kim Gordon that Nirvana signed to DGC in 1990, and both bands did a two-week tour of Europe in the summer of 1991, as documented in the 1992 documentary, 1991: The Year Punk Broke.