Bohr-Sommerfeld model by Ciro Santilli 32 Updated Created
Refinement of the Bohr model that starts to take quantum angular momentum into account in order to explain missing lines that would have been otherwise observed TODO specific example of such line.
They are not observe because they would violate the conservation of angular momentum.
TODO confirm year and paper, Wikipedia points to: zenodo.org/record/1424309#.yotqe3xmjhe