Add: 8) How to represent relations (esp. many-to-many) between non-hierarchical resources? The answers I have seen are either variations of "represent the rel

Add: 8) How to represent relations (esp. many-to-many) between non-hierarchical resources? The answers I have seen are either variations of "represent the relation as a resource" (is tying the relation resource's lifetime to that of the things related RESTful?), or "represent the relation as a property on both resources" (is it RESTful to reflect the update of a property on one object in another?).