article: Leonhard Euler
links: Johann Bernoulli Basel Saint Petersburg Russian Academy of Sciences Joseph-Louis Lagrange Reformed Church Euler diagram University of Basel Euler's homogeneous function theorem Euler's polyhedron formula Russian Empire Switzerland Euler-Bernoulli Beam Theory Euler's totient theorem Riehen Pierre-Simon Laplace Swiss franc Euler's totient function Euler–Mascheroni constant Euler's identity Lutheran Church Germany Euler characteristic Russia Calvinism