https://www.startquestion.com/blog/understand-customer-loyalty-with-the-apostle-model/
Services Virtuous Circles and the Tripple Bottom Line
https://www.tradigenia.es/uploads/BRDBhUXD/SERVICE_PROFIT_PEOPLE_PLANET.pdf
Drivers and barriers of circular economy business models: Where we are now, and where we are heading
https://www.sciencedirect.com/science/article/pii/S0959652621042153
