T. Burkhardt, S. Özkurt, F. Schimpf, and W. Fichter. Proceedings of the 79th Annual Forum of the Vertical Flight Society, West Palm Beach, Florida, USA, Vertical Flight Society, (May 2023)
T. Richter, B. Rothaupt, W. Fichter, and B. Grebing. Proceedings of the VFS International 76th Annual Forum, The Vertical Flight Society, The Vertical Flight Society, (October 2020)