semicolons: lists with commas inside the items
Semicolons when list items already have commas.
When the items in a list contain commas, separate the items with semicolons: the clerk from Dallas, Texas; the editor from Reno, Nevada; and the intern from Ames, Iowa. Ordinary short lists take commas.
Examples
UseWe called shops in Tulsa, Oklahoma; Phoenix, Arizona; and Reno, Nevada.
AvoidWe called shops in Tulsa, Oklahoma, Phoenix, Arizona, and Reno, Nevada.