Leonhard (ˈleːɔnhart). 1707–83, Swiss mathematician, noted esp for his work on the calculus of variation: considered the founder of modern mathematical analysis

Ulf (Svante) von (ʊlf fɔn). 1905–83, Swedish physiologist: shared the Nobel prize (1970) for physiology or medicine with Julius Axelrod and Bernard Katz for their work on the catecholamines: son of Hans von Euler-Chelpin

Swiss mathematician who made many contributions to numerous areas of pure and applied mathematics, physics, and astronomy. He was one of the first to develop the methods used in differential and integral calculus, and he introduced much of the basic mathematical notation still used today.