ERD

It should be possible to graphically represent the academic API. The boxes represent possible top-level resources and the lines between the boxes represent relationships between the resources. An interesting point here is that depending on which direction you look the data will be different. If you look at enrollments from the classes perspective, the data would include which students are enrolled in the class and perhaps data about each student, such as email address, class standing, major, etc. If you look at the relationship from the students perspective, the enrollments would be which classes the student is enrolled in, when are the classes taught, who the instructors are, etc. The relationship exists, but the context is different. Perhaps every entity (rectangle) could be a top-level resource.  In some instances, the relationship line could represent such critical business processes that it should be a top-level resource.

This diagram was provided by a consultant working with MIT.