WereMaurice Elvey and Arthur Lubin both from the USA?
Maurice Elvey Maurice Elvey (11 November 1887 – 28 August 1967) was the most prolific film director in British history. He directed nearly 200 films between 1913 and 1957. During the silent film era he directed as many as twenty films per year. He also produced more than fifty films - his own as well as films directed by others.
Arthur John Booker Arthur John Booker, M.D. (October 31, 1881 – August 25, 1957) was a prominent community activist and health advocate who worked in Des Moines, Iowa and Los Angeles, California. He also served as a physician with the 365th Infantry Regiment of the 92nd Division during World War I, where many of the African American soldiers served.