Haven't posted about a canceled gig in awhile. Anyway, found mention of a festival to include the GD, Ike & Tina Turner, Traffic, Stevie Wonder, the Allman Brothers and others, scheduled for June 13, 1970 per the post title. Course the GD played in Hawaii that day. Sounds like a big old event to have been still mentioned only two weeks ahead of time and then canceled. Ouches all around, I guess.
Anyway, I also wanted to try out the embedding function from Google Books, so here goes:
That's Billboard, May 30, 1970, p. 2, bottom of 2nd column then up to third. Accessed via Google Books.