The above three models define supply chains purely from a traditional perspective of product flow. However, with the growing importance of services and service industry, Ellram et al, (2004), Understanding and Managing Service Supply Chain, The Journal of Supply Chain Management, Vol. 40, 17-32, adapted this manufacturing approach into a new line of service thinking that uses service capacity and delivery, instead of products to classify supply chains as the key processes. This service supply model captures customer-supplier relationship via an end-to-end supplier and customer process that include capacity and demand management, cash flows and service delivery management, and just like manufacturing supply chain, customer relationship management. This is a very good approach that identifies relationship management but limited in that services are intangible and this makes them difficult to visualise and measure.