Ronald Radosh (15 de julio de 2021). «‘Sleeper Agent’ Review: From Moscow to Oak Ridge». Wall Street Journal(en inglés). Consultado el 3 de junio de 2025. «Abram Koval, was a Russian Jew [...] ended up in Sioux City, Iowa, a location chosen for him by a Jewish settlement organization [...] Ethel Shenitsky also arrived in Sioux City, and she and Abram married».