The Bohr-Kramers-Slater theory
(Bohr, Kramers, and Slater 1924; Hendry 1981; Kragh 2009)
Bohr, Niels, Hendrik Anton Kramers, and John Clarke Slater. 1924.
“The Quantum Theory of Radiation.” The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science 47 (281): 785–802.
https://doi.org/10.1080/14786442408565262.
Hendry, John. 1981.
“Bohr-Kramers-Slater: A Virtual Theory of Virtual Oscillators and Its Role in the History of Quantum Mechanics.” Centaurus 25 (2): 189–221.
https://doi.org/10.1111/j.1600-0498.1981.tb00644.x.
Kragh, Helge. 2009. “Bohr—Kramers—Slater Theory.” In Compendium of Quantum Physics, 62–64. Springer.