found: Romero, F.E. Los Four : Almaraz, de la Rocha, Lujan, Romero, 1973:leaf 15 (Roberto de la Rocha; Beto Rocha; b. in Wilmar, Calif.; Mexican American artist)
found: Data from Image Associates for Los Four [MP] 1975 (subj.)(Beto de la Rocha; Mexican American artist)
found: Union list of artist names, viewed December 16, 2022(Rocha, Roberto de la (Mexican American muralist, active 1973); variants: De la Rocha, Roberto; La Rocha, Robert de; Rocha, Beto; active in Los Angeles, Calif.)
found: Wikipedia, viewed December 16, 2022(Robert de la Rocha; Roberto Isaac "Beto" de la Rocha; born November 26, 1937; American painter, graphic artist, and muralist) (Los Four; active from 1973-1983: Chicano artist collective in Los Angeles, Calif.)