Question: Timber! was written by a singer who had a group with his brothers, Robin and who?

full_context: Document 1: Timothy (song): "Timothy" is a song written by Rupert Holmes and recorded by The Buoys in 1970, presenting the unnerving story of three men trapped in a collapsed mine, two of whom apparently resort to cannibalism against the third (the eponymous character Timothy). The song managed to reach the U.S. "Billboard" Top 40 chart on April 17, 1971, remaining on the chart for eight weeks, peaking at #17, as listed in "The Billboard Book of Top 40 Hits" by Joel Whitburn. On the U.S. "Cash Box" Top 100, it spent two weeks at #13. In Canada, the song reached #9.
Document 2: The Bee Gees Sing and Play 14 Barry Gibb Songs: The Bee Gees Sing and Play 14 Barry Gibb Songs is the debut studio album by the English pop band the Bee Gees. (1967's "Bee Gees' 1st" was the "international" debut album). Released under the artist title "Barry Gibb & the Bee Gee's" "[sic]", it was released in November 1965 on the Australian Leedon label. It is a compilation of most of the Gibb brothers' singles that had been released over the previous three years in Australia, which accounts for the many different styles of music on it.
Document 3: Bee Gees: were a pop music group formed in 1958. Their lineup consisted of brothers Barry, Robin, and Maurice Gibb. The trio were successful for most of their decades of recording music, but they had two distinct periods of exceptional success: as a popular music act in the late 1960s and early 1970s, and as prominent performers of the disco music era in the mid-to-late 1970s. The group sang recognisable three-part tight harmonies; Robin's clear vibrato lead vocals were a hallmark of their earlier hits, while Barry's R&B falsetto became their signature sound during the mid-to-late 1970s and 1980s. The Bee Gees wrote all of their own hits, as well as writing and producing several major hits for other artists.
Document 4: Timber! (Bee Gees song): "Timber!" is a song recorded by the Bee Gees, written by Barry Gibb. The song was released in Australia as their second single in July 1963, backed with "Take Hold of That Star". It was later included on the group's first album "The Bee Gees Sing and Play 14 Barry Gibb Songs".
Document 5: Jumbo (Bee Gees song): "Jumbo" is a song released by the Bee Gees, written by Barry, Robin & Maurice Gibb. It was released as a double A side with "The Singer Sang His Song" but featured as the lead track in some territories.
Document 6: The Singer Sang His Song: "The Singer Sang His Song" is a song written by Barry, Robin and Maurice Gibb and recorded by the English rock group Bee Gees, released in early 1968 as a single along with Jumbo. In some countries the song was the B-side of Jumbo but in others they were promoted as a double A-side.
Document 7: Maurice Gibb: Maurice Ernest Gibb, CBE ( ; 22 December 1949 – 12 January 2003) was a singer, songwriter, multi-instrumenatalist and record producer, who achieved fame as a member of the pop group the Bee Gees. Although his brothers Barry and Robin Gibb were the group's main lead singers, most of their albums included at least one or two compositions by Maurice, including "Lay It on Me", "Country Woman" and "On Time". The Bee Gees were one of the most successful rock-pop groups ever. Gibb's role in the group focused on melody and arrangements, providing backing vocal harmony and playing a variety of instruments.
Document 8: Robin Gibb: Robin Hugh Gibb (22 December 1949 – 20 May 2012) was a singer, songwriter and record producer, who gained worldwide fame as a member of the pop group the Bee Gees, with his brothers Barry and Maurice Gibb, his fraternal twin. Robin Gibb also had his own successful solo career.
Document 9: Tomorrow Tomorrow (Bee Gees song): "Tomorrow Tomorrow" is a song by the Bee Gees written by Barry and Maurice Gibb. The song was originally intended to be recorded by Joe Cocker. It was the first Bee Gees single released after Robin Gibb had quit the group which was now down to a trio featuring Barry Gibb, Maurice Gibb, and drummer Colin Petersen.
Document 10: Robin Gibb: Robin Hugh Gibb (22 December 1949 – 20 May 2012) was a singer, songwriter and record producer, who gained worldwide fame as a member of the pop group the Bee Gees, with his brothers Barry and Maurice Gibb, his fraternal twin. Robin Gibb also had his own successful solo career.
Document 11: Maurice Gibb: Maurice Ernest Gibb, CBE ( ; 22 December 1949 – 12 January 2003) was a singer, songwriter, multi-instrumenatalist and record producer, who achieved fame as a member of the pop group the Bee Gees. Although his brothers Barry and Robin Gibb were the group's main lead singers, most of their albums included at least one or two compositions by Maurice, including "Lay It on Me", "Country Woman" and "On Time". The Bee Gees were one of the most successful rock-pop groups ever. Gibb's role in the group focused on melody and arrangements, providing backing vocal harmony and playing a variety of instruments.
Document 12: Bee Gees' 1st: Bee Gees' 1st is the third studio album by English band Bee Gees, and their first international full-length recording after two albums distributed only in Australia and New Zealand. "Bee Gees' 1st" was the group's debut album for the UK Polydor label, and for the US Atco label. "Bee Gees 1st" was released on 14 July 1967 in the UK. On 9 August it entered the UK charts, on that same day, the album was released in the US, and it entered the US charts on 26 August. After its release, the band became more self-sufficient, producing and mixing many of their own releases.
Document 13: Robin's Reign: Robin's Reign was the first solo album by singer Robin Gibb, a member of the Bee Gees with his brothers Barry and Maurice. Robin had left the group following a disagreement with his brother Barry over who should sing lead vocals. The album was not a commercial success, though it did spawn Gibb's solo hit, "Saved by the Bell" (UK #2). The other songs in the album were produced by Gibb, and the rest was produced with his (then new) manager, Vic Lewis. This album was reissued by RSO Records in 1978 and reissued in 1991 on Spectrum Records. The album had a limited CD release in Germany and was made available digitally on Amazon and Spotify in 2011 and iTunes the following year. Gibb would not release another solo album until 1983.
Document 14: The Ultimate Bee Gees: The Ultimate Bee Gees is a compilation album released to coincide with the 50th anniversary of the Bee Gees. Although the group did not start recording until 1963 on Festival Records in Australia, they began calling themselves the "Bee Gees" in 1959 after several name changes such as "Wee Johnny Hayes and the Bluecats", "The Rattlesnakes" and "BG's". Each disc is themed with the first containing more upbeat songs, called "A Night Out", and the second containing slower songs and ballads, called "A Night In", though the cover art does not distinguish this theme. Liner notes were written by Sir Tim Rice. This also marks the return of the 1970s era logo on an official Bee Gees release, which was last used on the Bee Gees' 1983 single "Someone Belonging to Someone".
Document 15: Barry Gibb: Barry Alan Crompton Gibb, {'1': ", '2': ", '3': ", '4': "} (born 1 September 1946) is a singer, songwriter, musician, and record producer who rose to worldwide fame as a co-founder of the group Bee Gees, one of the most commercially successful and critically acclaimed groups in the history of popular music, with his brothers, Robin and Maurice Gibb. The three brothers also formed a songwriting partnership beginning in 1966.
ground_truth: Maurice Gibb