Answer by taking a quote from the following article:

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.

As Hughes and Plath were legally married at the time of her death, Hughes inherited the Plath estate, including all her written work. Hughes has been condemned repeatedly for burning Plath's last journal, saying he "did not want her children to have to read it." He lost another journal and an unfinished novel and instructed that a collection of Plath's papers and journals should not be released until 2013. Hughes has been accused of attempting to control the estate for his own ends, although royalties from Plath's poetry were placed into a trust account for their two children, Frieda and Nicholas.  Still the subject of speculation and opprobrium in 1998, Hughes published Birthday Letters that year, his own collection of 88 poems about his relationship with Plath. Hughes had published very little about his experience of the marriage and Plath's subsequent suicide, and the book caused a sensation, being taken as his first explicit disclosure, and it topped best seller charts. It was not known at the volume's release that Hughes was suffering from terminal cancer and would die later that year. The book went on to win the Forward Poetry Prize, the T. S. Eliot Prize for Poetry, and the Whitbread Poetry Prize. The poems, written after Plath's death, in some cases long after, try to find a reason why Plath took her own life.  In October 2015 the BBC Two documentary Ted Hughes: Stronger Than Death examined Hughes' life and work and included audio recordings of Plath reciting her own poetry. Their daughter Frieda spoke for the first time about her mother and father.  In 2017 it was revealed that letters written by Plath between February 18, 1960 and February 4, 1963 claim that Hughes beat Plath two days before she had a miscarriage in 1961, and that Hughes told Plath he wished that she was dead. The letters were sent to Dr. Ruth Barnhouse (then Dr. Ruth Beuscher).

What else did he publish?