1. Juran's Quality Handbook”;Juran,1999
2. I. Lopes, E.P. Nunes, S.D. Sousa, D. Esteves, Quality improvement practices adopted by industrial companies in Portugal, Lecture Notes in Eng. and Computer Science: Proceedings of the World Congress on Engineering 2011, WCE 2011, 6-8 July, 2011, London, UK, 696-701.
3. N. Rodrigues, “Aplicação de ferramentas da Qualidade para melhoria da produção numa empresa de soluções industriais”, MSc Thesis in Quality Eng. and Mgmt, University of Minho, 2016.
4. H. Teixeira, I. Lopes, S. Sousa, Prioritizing Quality Problems in SMEs: A Methodology, The TQM Journal, 27:1 (2015) 2-21.
5. D.C. Montgomery, “Introduction to Statistical Quality Control”, Sixth Edition, Arizona State University, John Wiley & Sons, Inc., 2009.