Revisiting Kepler's Laws of Equal Areas and Ellipses for the Earth
Rhythmos, Diathige, Trope
Riccioli Measures the Stars: Observations of the telescopic disks of stars as evidence against Copernicus and Galileo in the middle of the 17th century
Rise and fall of the old quantum theory
Robert H. Kraichnan
Rosenfeld, Bergmann, Dirac and the Invention of Constrained Hamiltonian Dynamics
Rutherford, Radioactivity, and the Atomic Nucleus