Question: Lionel Friedberg and Ralph Staub, have which mutual occupations?

Related documents: [0]  [DOC] Ralph Staub (July 21, 1899 in Chicago, Illinois – October 22, 1969, Los Angeles, California) was a movie director, writer and producer. [END] 
[1]  [DOC] Lionel Friedberg is a documentary film director, producer and writer who has written or produced films for Animal Planet, CBS, PBS, the History Channel, the Discovery Channel and National Geographic Channel. He has 18 credits as Director of Photography on feature motion pictures, and has worked all over the world on both dramatic and nonfiction productions. [END]  
Answer: director, writer and producer
director, writer and producer