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

Context paragraphs:
Ralph Staub: Ralph Staub (July 21, 1899 in Chicago, Illinois – October 22, 1969, Los Angeles, California) was a movie director, writer and producer.

A Sacred Duty: A Sacred Duty, subtitled "Applying Jewish values to help heal the world," is a 2007 60-minute documentary from Jewish Vegetarians of North America (JVNA), written and produced by Lionel Friedberg.  The film focuses on Jewish teachings about caring for the earth, treatment of animals, and the environment, with a focus on vegetarianism.  Interviews with rabbis, activists, and scholars are interspersed with footage and stills illustrating the points being discussed.

Scotty Bowers: George Albert "Scotty" Bowers (born July 1, 1923) is a former Marine who, from the 1940s to the 1980s, was a Hollywood pimp.  Stories of his exploits circulated for many years, and were alluded to in books such as Hollywood Babylon.  Bowers finally decided to talk publicly about his life when most of the people involved were dead and could no longer be affected by his revelations.  In 2012 the publication of his memoir "Full Service", written by Lionel Friedberg from 150 hours of interviews, drew publicity, including a profile in the" New York Times", and a feature on "CBS News Sunday Morning".  One journalist has written, "He has a savant-like quality: a result of his refusal to be embarrassed by sex."

Lionel Friedberg: 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.

Full Service (book): Full Service: My Adventures in Hollywood and the Secret Sex Lives of the Stars is a "tell all" book about the sex lives of Hollywood stars from the late 1940s to the early 1980s by Scotty Bowers, with Lionel Friedberg as a contributing author.  Bowers makes many claims about the sex lives of many people, most of whom were associated with the Hollywood movie industry during that period.  The book, which was vetted by a libel lawyer before publication, was refused by several publishers before ultimately being accepted by Grove Press and Grove/Atlantic.  Matt Tyrnauer, director of "", is currently in production on a documentary film about Bowers's life.

Hollywood in Uniform: Hollywood in Uniform is a 1943 American short documentary film directed by Ralph Staub.  It was nominated for an Academy Award at the 16th Academy Awards for Best Short Subject (One-Reel).

Keystone Hotel (film): Keystone Hotel (1935) is a two-reel comedy short subject, directed by Ralph Staub and released by the Vitaphone Corporation through Warner Bros.  Pictures.  Inspired by the silent comedies produced by Mack Sennett, the film reunites many of Sennett's former stars.

Screen Snapshots: Screen Snapshots were a series of documentary short subjects produced by Columbia Pictures between 1924 and 1958.  They featured behind-the-scenes footage of Hollywood stars of the day at various Hollywood events or parties.  From about 1930, these short documentaries were almost exclusively written, produced and directed (and occasionally edited and narrated) by Ralph Staub, until the series was discontinued in 1958.  They usually ran for 9 or 10 minutes and were shown in cinema theatres like newsreels alongside main features.

Richard H. Schwartz: Richard H. Schwartz (born April 10, 1934) is a professor emeritus of mathematics at the College of Staten Island; President of the Jewish Vegetarians of North America (JVNA); and co-founder and coordinator of the Society of Ethical and Religious Vegetarians (SERV).  He is best known as a Jewish vegetarian activist and advocate for animal rights in the United States and Israel.  His writings inspired the 2007 documentary film, "A Sacred Duty: Applying Jewish Values to Heal the World", directed by Lionel Friedberg.  Schwartz and JVNA have arranged to give away about 40,000 complimentary DVDs of the video and have arranged to have it seen freely at aSacredDuty.com.

What, No Men!: What, No Men!  is a 1934 American short comedy film directed by Ralph Staub, and filmed in Technicolor.  It was nominated for an Academy Award in 1934 for Best Short Subject (Comedy).

Supporting paragraphs: Lionel Friedberg Ralph Staub
Answer: director, writer and producer