BARRA RALPH. (1983). PUTTING QUALITY CIRCLES TO WORK: A PRACTICAL STRATEGY FOR BOOSTING PRODUCTIVITY & PROFITS. MCGRAW-HILL.
Chicago-referens (17:e uppl.)BARRA RALPH. PUTTING QUALITY CIRCLES TO WORK: A PRACTICAL STRATEGY FOR BOOSTING PRODUCTIVITY & PROFITS. LONDON: MCGRAW-HILL, 1983.
MLA-referens (9:e uppl.)BARRA RALPH. PUTTING QUALITY CIRCLES TO WORK: A PRACTICAL STRATEGY FOR BOOSTING PRODUCTIVITY & PROFITS. MCGRAW-HILL, 1983.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.