S-J-D Regulators
There are regulators designs similar to the Jung-Sulzer-Didden around before their articles were published. If you have an old National Semiconductor application data books you will find regulators that look to be the foundation for this implementation.
While the implementation is different it may or may not be new for the time “it is still very well done” however I believe audio performance claims made in the articles for the circuit is new. The design offers great low noise performance and the ability to track dynamic changes in at the load with excellent stability. The keys are precision voltage reference, the high-speed transistor, the ultra low noise opamp, and the added ground sense implementation for audio.
My understanding is the only copyright protect belongs to the author work and what he is done in the development of the documentation for Audio Amateur-Audio Express magazine. They are no patents or trademarks other than the author name and no intellectual property issues.
To have intellectual property issues, as I understand it, this would have to have information i.e. a process, a method, or a design secret one has acquired at a company. Now, the person is at another company and if he implements the information gained at his previous employer that could be an intellectual issue. Therefore, the act of publishing the article for users, and users paying for the article seems to cancel out the intellectual property rights.
So using this circuit is ok for your home project. However, it would make good sense to alter and improve the design for commercial use.