13. José Celso. "Os tempos são outros." Transcribed fromA Classe Operária no. 134, (1979 February-March).

13. José Celso. "Os tempos são outros." Transcribed fromA Classe Operária no. 134, (1979 February-March)., Box: 9. Eduardo Sarno Collection of Leftist Movements in Brazil, 2002-03. Benson Latin American Collection, The University of Texas at Austin. https://archives.lib.utexas.edu/repositories/4/archival_objects/372887 Accessed September 27, 2026.