"New concerns function with Queens capital". The Daily Star. April 16, 1927. p. 16. E. Trump & Son Company, Inc., of Jamaica, has been formed with $50,000 capital to deal in realty.
Mason, Joseph B. (December 1, 1940). "Biggest one-man building show". American Builder and Building Age. ProQuest853825839. When [Fred Trump] was 27 years old he started his first small home building job on his own, but with some financial backing from his mother.(subscription required)