A list of entity types, by itself, doesn't provide enough information to serve as a reference model.

Within an environment: A reference model does not attempt to describe "all things."

A reference model is used to clarify "things within an environment" or a problem space.

A third use of a reference model is to improve communication between people.

A fourth use of a reference model is to create clear roles and responsibilities.

I think part of your problem is that you don't understand the concept of a reference model.

In 2012 the team released the trial master file reference model.

In addition, the experts' chair can be used as a reference model.

A single ontology is used as a global reference model in the system.

A reference model is available for the contestants to work off.