CROCKER, O. L. (1984). Quality Circles A Guide To Participations And Productivity Olga L. Crocker, John Sik Leung Chiu. Methuen.
Lua i Stíl Chicago (17ú heag.)CROCKER, Olga L. Quality Circles A Guide To Participations And Productivity Olga L. Crocker, John Sik Leung Chiu. Methuen, 1984.
Lua MLA (8ú heag.)CROCKER, Olga L. Quality Circles A Guide To Participations And Productivity Olga L. Crocker, John Sik Leung Chiu. Methuen, 1984.
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