Perhaps it's a very simple thing to do, but I'm a bit confused.
I want to define a simple model:
children: 0..n -> Person
contacts: 0..n -> Person
That is, each Person has a list of other persons.
The logical way is to define "contacts" as a reference with 0..n cardinality, not as a child.
(The structure I want to get is graph).
But references do not have 0..n cardinality.
What is the recommended approach in this case? Should I define the additional concept, like "PersonList"?
Is there a reason that children have 0..n cardinality and references do not?