! note: Note the misdating to 1969 by Grushkin's AOR.
! ref: AOR 2.118: October Calendar; The Matrix, San Francisco, 1969 [sic]; Artists: George Chacona, Marty Rice (Grushkin 1987, 166).
! ref: Grushkin, Paul. 1987. The Art of Rock: Posters from Presley to Punk. Artworks photographed by Jon Sievert. New York: Abbeville Press Publishers.! note: Note dates 10/8/68, 10/9/68, 10/10/68, for searchability.
! seealso: "Hartbeats as Tempo Etudes," http://jgmf.blogspot.com/2012/11/ln-jg1968-10-30hartbeats163minssbd.html.