Here is a great review of The Wailers performance at Sundown, Edmonton, June 3, 1973, a performance that was broadcast on the BBC. The review was published in Melody Maker on June 9, 1973.
Bob Marley, Bob Marley and the Wailers, Roots and Culture, The Wailers
The Wailers Live at Sundown, Edmonton, June 3, 1973
LEGENDARY REGGAE 
video is not edmonton