Question: Were Upton Sinclair and Daniil Kharms both writers?

Context paragraphs:
Upton Sinclair House: The Upton Sinclair House, located at 464 N. Myrtle Avenue, Monrovia, California, was the home of American novelist Upton Sinclair between 1942 and 1966.  It is a 1923 Neo-Mediterranean building in a district of similar houses, located in suburban Los Angeles, in the San Gabriel Valley.  Most of his later works were written while he lived here.  He had converted the rear garage into his study.  The grounds also include a concrete vault where he kept all his papers.

Clownery (film): Clownery (Russian: КлоунАда , translit.  "Klounada") is a black-and-white and colour 1989 Soviet idependent film directed by Dmitrii Frolov.  It is based on Daniil Kharms novel "Situations".

Mental Radio: Mental Radio: Does it work, and how?  (1930) was written by the American author Upton Sinclair and initially self-published.  This book documents Sinclair's test of psychic abilities of Mary Craig Sinclair, his second wife, while she was in a state of profound depression with a heightened interest in the occult.  She attempted to duplicate 290 pictures which were drawn by her brother.  Sinclair claimed Mary successfully duplicated 65 of them, with 155 "partial successes" and 70 failures.  The experiments were not conducted in a controlled scientific laboratory environment.

The Coal War: The Coal War is a novel by Upton Sinclair.  It is a sequel to "King Coal" and documents the continuing exploits of that novel's protagonist, Hal Warner.  When Sinclair submitted the novel for publication in 1917, it was rejected as being insufficiently interesting from a novelistic standpoint.  After this, the manuscript remained in limbo until 1976, when it was finally published by the Colorado Associated University Press.  The book was published eight years after Sinclair's death.

Daniil Kharms: Daniil Kharms (Russian: Дании́л Ива́нович Хармс ; 30 December [O.S. 17 December] 1905  – 2 February 1942) was an early Soviet-era surrealist and absurdist poet, writer and dramatist.

Upton Sinclair: Upton Sinclair Jr. (September 20, 1878 – November 25, 1968) was an American writer who wrote nearly one hundred books and other works in several genres.  Sinclair's work was well known and popular in the first half of the twentieth century, and he won the Pulitzer Prize for Fiction in 1943.

Annex Press: ANNEX PRESS is an experimental small press founded in 1973 by Julian Kabza, aka Tod Kabza, writer, publisher, editor, visual artist.  In the 1970s and 80's, Annex published work of new music documentation, conceptual art and texts by French, Russian and American experimental writers: Bob Perelman, Blue Gene Tyranny, Ron Silliman, Rosmarie Waldrop, Alan Davies, Bruce Andrews, Anne Waldman, Alain Veinstein and Yuri Mamleyev, Daniil Kharms (Daniil Ivanovich Yuvachev), Anne-Marie Albiach, Ascher/Straus, Lyn Hejinian, John Latta, among them.  The Annex magazine edited by Julian Kabza appeared under varying titles; Biscuit (1976), Flora Danica (1976, Terraplane, 1977,and "Writing".  "Annexes", which are single author pamphlets include: Veinstein's "From A Reader's Notebook, translated by Rosmarie Waldrop).  Since the 1990s Annex Press has published in print, electronic, video, sound and film formats.  The annexpress.org website publishes work by Su Freidrich film maker, Tom Mandel, Steve Benson, Julian Kabza, Volodymyr Bilyk, Leanne Bridgewater, Isidore Isou, Anna O'Meara + Ian Tompson, american dancer-choreographer Mark Tompkins, Luc Riolon videographer - film maker, Kit Robinson.

The Jungle (1914 film): The Jungle (1914) is an American drama silent film made by the All-Star Feature Corporation starring George Nash.  The film is an adaptation of the 1906 book of the same name by Upton Sinclair, the only one to date.  Sinclair reportedly bought the negative of the film prior to 1916, hoping to market the film nationally after its initial release in 1914.  Sinclair himself reportedly appears at the beginning and end of the movie, as a sort of endorsement of the film.

California gubernatorial election, 1934: The California gubernatorial election, 1934 was held on November 6, 1934.  Held in the midst of the Great Depression, the 1934 election was amongst the most controversial in the state's political history, pitting conservative Republican Frank Merriam against former Socialist Party member turned Democrat Upton Sinclair, author of "The Jungle".  A strong third party challenge came from Commonwealth-Progressive Raymond L. Haight, a Los Angeles lawyer campaigning for the political center.  Much of the campaign's emphasis was directed at Sinclair's EPIC movement, proposing socialist reforms to cure the state's ailing economy.  Merriam, who had recently assumed the governorship following the death of James Rolph, characterized Sinclair's proposal as a step towards communism.

End Poverty in California movement: The End Poverty in California movement (EPIC) was a political campaign started in 1934 by famed socialist writer Upton Sinclair (best known as author of "The Jungle").  The movement formed the basis for Sinclair’s campaign for Governor of California in 1934.  The plan called for a massive public works program, sweeping tax reform, and guaranteed pensions.  It gained major popular support, with thousands joining End Poverty Leagues across the state.  EPIC never came to fruition due to Sinclair’s defeat in the 1934 election, but is seen as an influence on New Deal programs enacted by President Franklin D. Roosevelt.

Supporting paragraphs: Upton Sinclair Daniil Kharms
Answer: yes