Question: Colette and Sylvia Plath were both well-known what? 

Context articles: Colette
Letters Home: Correspondence 1950–1963
The Bell Jar
The Blue Flannel Suit
Aurelia Plath
Otto Plath
Sylvia (2003 film)
Ennui (sonnet)
Sylvia Plath
Sylvia Plath effect

Colette (] ; Sidonie-Gabrielle Colette, 28 January 1873 – 3 August 1954) was a French novelist nominated for the Nobel Prize in Literature in 1948.
 Her best known work, the novella "Gigi" (1944), was the basis for the film and Lerner and Loewe stage production of the same name.
 She was also a mime, an actress and a journalist.
Letters Home is a collection of letters written by Sylvia Plath to her family between her years at college, in 1950, and her death at age 30.
 Sylvia's mother, Aurelia Schober Plath, edited the letters and the collection was published by Harper & Row (US) and Faber & Faber (UK) in 1975.
The Bell Jar is the only novel written by the American writer and poet Sylvia Plath.
 Originally published under the pseudonym "Victoria Lucas" in 1963, the novel is semi-autobiographical, with the names of places and people changed.
 The book is often regarded as a "roman à clef" since the protagonist's descent into mental illness parallels Plath's own experiences with what may have been clinical depression.
 Plath died by suicide a month after its first UK publication.
 The novel was published under Plath's name for the first time in 1967 and was not published in the United States until 1971, in accordance with the wishes of both Plath's husband, Ted Hughes, and her mother.
 The novel has been translated into nearly a dozen languages.
 The novel, though dark, is often read in high school English classes.
"The Blue Flannel Suit" is a poem by Ted Hughes published in 1998 in his book "Birthday Letters".
 The 30th of 88 poems in the collection, "The Blue Flannel Suit" is one of several in the series explicitly about his wife Sylvia Plath.
 Prior to the series, Hughes had rarely discussed their relationship or Plath's death or responded to claims by some critics that he bore some responsibility for her state of mind and death.
Aurelia Frances Plath (née Schober; April 26, 1906 – March 11, 1994) was the wife of Otto Emil Plath, the mother of the American poet Sylvia Plath, and her brother Warren, and the grandmother of Frieda Rebecca Hughes and Nicholas Farrar Hughes.
Otto Emil Plath (April 13, 1885 – November 5, 1940) was a German American author, a professor of biology and German at Boston University, and an entomologist, with a specific expertise on bees.
 He was the father of American poet Sylvia Plath, Warren Plath, and the husband of Aurelia Plath.
 He wrote the 1934 book, "Bumblebees and Their Ways".
 He is notable for being the probable subject of one of his daughter's most well-known poems, "Daddy".
Sylvia is a 2003 British biographical drama film directed by Christine Jeffs and starring Gwyneth Paltrow, Daniel Craig, Jared Harris, and Michael Gambon.
 It tells the true story of the romance between prominent poets Sylvia Plath and Ted Hughes.
 The film begins with their meeting at Cambridge in 1956 and ends with Sylvia Plath's suicide in 1963.
"Ennui" is a sonnet by Sylvia Plath published for the first time in November 2006 in the online literary journal "Blackbird" .
 Sylvia Plath wrote the Petrarchan sonnet “Ennui” during her undergraduate years at Smith College.
Sylvia Plath ( ; October 27, 1932 – February 11, 1963) was an American poet, novelist, and short story writer.
 Born in Boston, she studied at Smith College and Newnham College at the University of Cambridge before receiving acclaim as a poet and writer.
 She married fellow poet Ted Hughes in 1956, and they lived together in the United States and then in England.
 They had two children, Frieda and Nicholas, before separating in 1962.
 Plath was clinically depressed for most of her adult life, and was treated multiple times with electroconvulsive therapy (ECT).
 She committed suicide in 1963.
The Sylvia Plath effect is the phenomenon that poets are more susceptible to mental illness than other creative writers.
 The term was coined in 2001 by psychologist James C. Kaufman.
 Although many studies (e.g., Andreasen, 1987; Jamison, 1989; Ludwig, 1995) have demonstrated that creative writers are prone to experience mental illness, this relationship has not been examined in depth.
 This early finding has been dubbed "the Sylvia Plath effect", and implications and possibilities for future research are discussed.
 Kaufman's work further demonstrated that female poets were more likely to experience mental illness than any other class of writers.
 In addition, female poets were more likely to be mentally ill than other eminent women, such as politicians, actresses, and artists.