Audi: What do the four rings on its logo stand for?

This Is The True Meaning Behind The Audi Logo

Four rings – four brands

The Meaning & History Of Audi & The Four Ring Logo

Luxury Car Logos: See What They Mean - Kelley Blue Book

History of the Four Rings

Four rings – four brands

What's the Meaning Behind the Audi Logo?

Why Does the Audi Logo Have Four Rings? - Audi Club North America

75th anniversary of the four rings

Which car company has the logo with four rings? - Quora