Who is the author in the National Academy of Sciences for Proceedings of the National Academy of Sciences of the United States of America?
SELECT ?value WHERE { wd:Q1146531 p:P50 ?s . ?s ps:P50 wd:Q270794 . ?s pq:P1932 ?value}
proceedings of the national academy of sciences of the united states of america: Q1146531 national academy of sciences: Q270794