Lancaster, PA: The American Physical Society, 1950. Wraps. First Edition. 189-362 pp. 4to. Green paper wraps that are quite clean inside and out, very minor age toning to spine, pencil notation of date at upper right corner of cover. Very Good.
The first of these papers confirmed the decay of a free neutron. The second paper by John M. Robston, the scientist who observed the first decay, comments on the confirmation.