KIRAN, D. R. Total quality management: key concepts and case studies. Amsterdam: Elsevier/Butterworth-Heinemann, 2017. ISBN 978-0-12-811035-5 .
MENDENHALL, W. and T. SINCICH. Statistics for engineering and the sciences. Sixth edition. Boca Raton: CRC Press, Taylor & Francis Group, 2016. ISBN 978-1-4987-2885-0 .
BENCSIK, A. Knowledge management initiatives and strategies in small and medium enterprises. Hershey: IGI Global, 2017. ISBN 978-1-5225-1642-2 .
MILTON, J. S., J. C. ARNOLD and L. KWONG. Probability and statistics: for engineering and the computing sciences. Singapore: McGraw-Hill, c2013. ISBN 978-0-07-108785-8 .