Apologies, I was looking at an older version of bibframe.rdf (from 
mid-2016).  The current version (2017-02) has subclass of owl:Thing.

-- Darren

On 5/2/17 4:51 PM, Darren Weber wrote:
> This is a handy graphical representation of common practice for OWL 
> ontologies:
> - 
> Almost everything in BF2 is a subclass of rdfs:Resource.  In other 
> words, BF2 classes "sidestep" owl:Thing (for almost everything except 
> bf:Agent) to assert subclass relations directly on rdfs:Resource.  As 
> this seems, to me, to be an unusual practice for an ontology (OWL 
> ontology), I'd like to understand the reasoning behind it.  (When 
> developing MADSRDF, the root class is owl:Thing, so this seems to be a 
> departure from another LC ontology practice.)
> Thanks,
> Darren

Darren L. Weber, Ph.D.
Cognitive Scientist and Software Engineer
Digital Library Systems and Services

Stanford University Libraries
Lathrop Library
518 Memorial Way  MC:3101
Stanford, CA 94305-3101