Buy 3, pay for 2 — use code TRIPLEUS at checkout. Buy 3: 50% off the 3rd with TRIPLEUS50 Used books by Ursula Summ from $20.65 | HamelynUrsula Summ is a renowned German author specializing in non-fiction works. Her primary focus centers on nutrition, metabolism, and health. She is world-renowned for her fundamental work on the food-combining diet, Trennkost. Throughout her prolific career, she has published a total of 44 books. Born in Hofheim am Taunus, she has dedicated her career to promoting healthy eating habits.