Great Britain, Physical Society Cambridge, 1947. Royal8vo. Without wrappers (as issued). Offprint from ""Physical Society Cambridge Conference Report"", 1947. Fine and clean. Pp. 177-180.
Offprint of Pais' first project in Copenhagen under Bohr. ""My first project [in Copenhagen] was a collaboration with Hulthén. It was a lengthy computational affair dealing with neutron-proton scattering. Our results were published in a paper that appeared in the Proceedings of the first international postwar physics conference."" Pais, A tale of two continents, p. 157.