Question: what is the American singer-songwriter who Erik Jacobsen work with best known for 

Context paragraphs:
Erik Jacobsen: Erik Jacobsen (born May 19, 1940) is an American record producer, song publisher and artist manager.  He is best known for his work in the 1960s with Tim Hardin, The Lovin' Spoonful, The Charlatans, Sopwith Camel, and later with Norman Greenbaum and Chris Isaak.  Though semi-retired, Jacobsen continues to manage many of his published songs and masters for various uses.

Anjani: Anjani Thomas (born July 10, 1959) is an American singer-songwriter and pianist, best known for her work with singer-songwriter Leonard Cohen, as well as Carl Anderson, Frank Gambale, and Stanley Clarke.  She became a solo artist in 2000.

Annie Jacobsen: Annie Jacobsen is an American investigative journalist, author and 2016 Pulitzer Prize finalist in history.  She was a contributing editor to the "Los Angeles Times Magazine" from 2009 until 2012.  Jacobsen writes about war, weapons, security and secrets.  Jacobsen is best known as the author of the 2011 nonfiction book "", which "The New York Times" called "cauldron-stirring."

Wayne Jacobsen: Wayne Jacobsen is an American author, best known for "He Loves Me!" , a nonfiction book about the Love of God.  He also collaborated on the writing of "The Shack" and helped create Windblown Media, the publishing company behind the phenomenon.  He was a pastor for 20 years and a Contributing Editor to "Leadership Journal" and has authored numerous articles on spiritual formation, relational community and engagement of culture.  As President of BridgeBuilders, he is also a nationally recognized specialist and mediator in resolving cultural and religious conflicts.  Jacobsen has become known for his expertise in the pros and cons of organized religion.

Eric Jacobsen: Eric N. Jacobsen (born February 22, 1960.  in New York City, New York) is the Sheldon Emery Professor of Chemistry and Chair of the Department of Chemistry and Chemical Biology at Harvard University.  He is a prominent figure in the field of organic chemistry and is best known for the development of the Jacobsen epoxidation and other work in selective catalysis.

Holger Jacobsen: Holger Jacobsen (30 October 1876 – 27 March 1960) was a Danish architect.  His best known work is Stærekassen, an extension to the Royal Danish Theatre on Kongens Nytorv in Copenhagen.

Danny Weis: Guitarist Danny Weis (born 28 September 1948 in Huntington Park, California) is best known as a founding member of both Iron Butterfly and Rhinoceros, as well as co-writer of Rhinoceros's only charting single, "Apricot Brandy".  Though he left Iron Butterfly after only one album due to internal tensions, his work was an influence in the band for most of their history, since his replacement Erik Brann made a conscious effort to imitate his playing.  Weis later recounted "Erik Braunn replaced me in Iron Butterfly, and if I remember correctly, he bought a lot of my equipment, some of my clothes, they tried to clone me basically..."

Norman Greenbaum: Norman Joel Greenbaum (born November 20, 1942) is an American singer-songwriter.  He is best known for writing and performing the 1969 song "Spirit in the Sky".

Chuck Carrington: Chuck Carrington (born 1968 in Lynchburg, Virginia) is an American actor best known for playing Petty Officer Jason Tiner on "JAG", and also starred as Renny Jacobsen in the independent feature thriller "The List", alongside Malcolm McDowell and Hilarie Burton.

Maria McKee: Maria Luisa McKee (born August 17, 1964) is an American singer-songwriter.  She is best known for her work with Lone Justice, her 1990 UK solo chart-topping hit, "Show Me Heaven", and her song "If Love Is a Red Dress (Hang Me in Rags)" from the film "Pulp Fiction".  She is the half-sister of Bryan MacLean, who was best known as a guitarist and vocalist in the band Love.

Supporting paragraphs: Erik Jacobsen Norman Greenbaum
Answer: "Spirit in the Sky"