Petition from Leo Szilard and Other Scientists to President Harry S. Truman.
Signatories:
R E Lapp
R S Mulliken
E P Wigner
George S. Monk
Leo Szilard
J. J. Nickson
W. H. Zachariasen
Francis R. Shonka
John A. Simpson jr.
Walter Bartky
John P. Howe

Frank Foote
https://catalog.archives.gov/id/6250638
Leó Szilárd