The kinds of model you draw depends on the purpose that you want to put them to. John describes a useful distinction between conceptual, specification, and implementation models.
The kinds of model you draw depends on the purpose that you want to put them to. John describes a useful distinction between conceptual, specification, and implementation models.

The kinds of model you draw depends on the purpose that you want to put them to. John describes a useful distinction between conceptual, specification, and implementation models.