On the Oxford comma

The Oxford Comma is always and eternally invariably correct, and knowing failure to use it is abomination punishable by death, or at least a failing mark. The delimiter of a comma-delimited list is a comma. In the fake and obviously-manufactured constructed situations where the comma-delimited comma-delimited-list can be unclear, it is also obviously clear that rewriting the sentence would be better AND that the situation was constructed specifically to create a situation where comma-delimiting a comma-delimited list might be confusing.

Source