allocation resource reference
A reference to uniquely identify a resource of an Allocation class. The reference is
provided as a pair of Resource References to the Allocation classes components. For example,
Products At Locations Allocation class has Products and
Locations components. Allocation reference (Products.name,
Locations.name) with values X and Y respectively, refers to the Allocation
resource which consists of resource with name ‘X’ from Class ‘Products’, and resource with
name ‘Y’ from Class ‘Locations’.