Avramouli, D., Karageorgos, A., Didakis, I,. Rapti, E., “Customer Relationship Management (CRM)”, Association of Greek Academic Libraries, Athens, 2015, https://repository.kallipos.gr/handle/11419/1486
Innovation and Entrepreneurship Unit, University of Macedonia, “CRM Systems”, Department of Business Organization and Management, Course Special Topics in Entrepreneurship, 2012, http://mke.uom.gr/documents/ODE/Lesson_6.pdf
Fitsilis, P., “Modern business information systems”, Athens: Association of Greek Academic Libraries, 2015, http://hdl.handle.net/11419/2256