Schweigert, Victoria-Anne, and Andreas Geyer-Schulz. “The Impact of the General Data Protection Regulation on the Design and Measurement of Marketing Activities: Introducing Permission Marketing and Tracking for Improved Marketing & CRM Compliance With Legal Requirements”. Journal of Marketing Development and Competitiveness 13, no. 4 (November 25, 2019). Accessed July 22, 2024. https://articlegateway.com/index.php/JMDC/article/view/2352.