1. Kallhoff C., Kotzab H., Supply Management Research, 257–272 (2016)
2. https://topqm.de/de/aktuelles/vda_6.3_yellow_print_3.3rd_completely_revised_editionjuly_2016.pdf [Accessed: 3 March 2021]
3. https://vdaqmc.de/fileadmin/redakteur/Publikationen/VDA_Band_SI_FAQ/FAQ_SI_VDA_6_0_DE_Maerz-2016.pdf [Accessed: 3 March 2021]
4. https://www.vda.de/de.html [Accessed: 14 January 2019]
5. ISO 9000:2015: Quality management systems Fundamentals and vocabulary (2015)