Radulescu, Vicentiu: Nonlinear Analysis, Mathematical Physics and Variational Calculus.Ramzan, Zulfikar: Cryptography and Information Security.Ratna: Rethnakaran, an electrical engineer from India describes his interests and philosophy of life. Provides links to mathematics, communication theory, and physics resources.Yann Renoux: Biography of the mathematician interested in statistical arbitrage, optimal execution, and transaction cost modeling.