Grace and Janis live

[CookOfTheHouse]

Last year, I think it was on Wolfgang's Vauls, I found a live performance by the airplane and I red the description of the concert and it said we could hear Janis jumping on stage and singing with Grace on the last track. I've been meaning to find this but I can't, has ayone else heard about it or has any idea of where I can find it?? Thanks!

[Egg Crisis]

You're probably thinking of this, the final three tracks being a jam featuring members of Jefferson Airplane, Quicksilver Messenger Service & Big Brother & The Holding Company at their New Year 31 Dec 1967 show.