Circular references

Explanation 1: A circular reference is a series of references where the last object references the first, resulting in a closed loop.

Explanation 2: A circular relationship exists when every occurrence of entity A has one or more occurrences of entity B; entity B has one or more occurrences of entity C; and entity C has one or more occurrences of entity A

A => B => C => A

You can prevent circular references by using a link table:

A => ABC
B => ABC
C => ABC