Ludwik Silberstein.  "Contribution to the Quantum Theory of Spectrum Emission: Spectra of Atomic Systems Containing a Complex Nucleus."  Offprint:  Philosophical Magazine, vol xxxix, January 1920. 

Original printed wrappers.pp 46-66.  Inscribed, "with the author's best regards, 21.I.1920".  $125

Silberstein was as we all know an interesting thinker, working early and with some elegance in relativity, though he did run into a spot of bother with Einstein in which the good Dr. Silberstein fared not so well. I've always rather "liked" Silberstein for his early work.