a German doctor of medicine and internist affiliated with the university hospital in Münster, specialized in endocrinology, diabetes and clinical nutrition. As former avocational computer chess programmer, supported by co-author Gaby von Rekowski, Reinhold Gellner is primary author of the chess program Nightmare .
- Nach dem Feiern kommt das Fasten: UKM Pressemitteilungen Archiv, February 28, 2019 (German)
- Nightmare's ICGA Tournaments
- Hiarcs Fan Page by Thorsten Czub