Styling external links, yea or nay? (opens in new tab)

Dear Reader, I have a question: should external (or outbound) links be styled differently from internal ones? For example, in a sentence like: ‘the recent events made me reconsider my earlier position on the matter,’ should the first link (to an external website) have a different style than the second (to another page on the same website)? I’d love to hear your thoughts in comments below. I’m particularly interested in existing UX research on the subject.