Other than BA, who has 4-class configuration on their a/c?

I believe Virgin was the first (or amongst the first) airlines to introduce a ‘premium economy’ class on their aircraft. BA followed suit later, and I would think both airlines do well out of such seats- they always appear full.

But what other airlines have introduced them, and did they have 3 classes to start with? Is the BA the only airline with a 4-class configuration on their long haul aircraft? Surely not…