José Ángel Gutiérrez (1944) American academic
quoted in "Racial Tactics Backfire", an article on page 12 of Texas Monthly Vol. 4 No. 7, July 1976 https://books.google.ca/books?id=zCwEAAAAMBAJ&pg=PA12. According to Brian B. Behnken on page 184 of the 2011 book Fighting Their Own Battles: Mexican Americans, African Americans, and the Struggle for Civil Rights in Texas https://books.google.ca/books?id=SYoy9QhqvloC&pg=PA184 this was said at a MAYO rally in 1969.