demonstrates both types of circular references. When a cell contains a reference to itself, it is a direct circular reference.
Notice that with the direct circular reference the argument for the SUM function includes a reference to cell C7.
In the indirect reference example, there are three items that all reference a different item.
Item A references Item C. Item B references Item A, and Item C references Item B.
While none of the cells contain a direct circular reference, each cell references another cell that eventually references back to itself, creating an indirect circular reference