Conversation so far:
How did Frank Sinatra get started in his career?
Frank Sinatra got his first break in 1935  with a local singing group, the 3 Flashes. Fred Tamburro, the group's baritone, admitted they took him because he owned a car.
Did Fred Tamburro and Frank Sinatra work together after the 3 Flashes?
Yes, Tamburro and Sinatra sang in the group known as the Hoboken Four

Question: Who else did Sinatra work with?
Self-contained rewrite: Who else did Frank Sinatra work with besides Fred Tamburro, the 3 Flashes and Hoboken Four?