The definitions of resource that can be found in literature show ambiguity, making the issue of handling the identification of a web resource very problematic.
Our approach restricts the nature of the web resource to that of a computational object. This choice is motivated by the fact that a resource is something that has to be addressable, and things like cars and people are not addressable for their nature. Hence, it is wrong in principle to use the same mechanism of addressing for entities that have such different sorts.
This paper by Valentina Presutti and Aldo Gangemi at SWAP2006 begins with a clear introduction to the issue of resource identity, and the ambiguity of the term resource itself. Then it goes on with a very smart OWL model attempting to articulate the various aspects of this concept. Maybe too smart and conceptual to become really popular, but interestingly enough, it goes against the popular Semantic Web assumption that URI can actually identify "non-addressable things", and is rather in the line of letting the referent entities outside of the identification framework.