From Serious Eats. Generally I've not been a fan of German Potato Salad, most of the ones I've had are undercooked/crunchy-hard potatoes drenched in so much vinegar they're almost impossible to eat. But then I'd never been a fan of the more common style of potato salad until I made my own with a decent recipe, and now I love it. So who knows? I'm convinced that good potato salads are impossible to buy, you really have to make them yourselves. Cole slaw is the same way. Actually, so is macaroni salad.
As I often do, rather than copy the recipe I'm simply providing a link to the Serious Eats website: