Question: Which of Robin Gibb's siblings were featured in Mythology?

full_context: Document 1: Saved by the Bell (song): "Saved by the Bell" is a 1969 single written and recorded by Robin Gibb. It was released in June 1969 and has been certified gold. It was the lead single on Gibb's debut album "Robin's Reign", released in early 1970. According to Vinyl Records, the song was co-produced by Kenny Clayton. Gibb also made a promotional video for this song. The song gained commercial success in Europe, but was a commercial failure in the US.
Document 2: In Our Own Time: In Our Own Time is a biography of the musical group, The Bee Gees. The story follows the Brothers Gibb, Barry, Robin and Maurice from their roots in Manchester, England through their emigration to Australia in 1958 to their international stardom in 1967, right up to the present, with new interviews done by Barry and Robin and archival footage of Maurice (who died in 2003). Many live performances are featured, along with video clips, TV performances and home movies from their early days.
Document 3: Their Greatest Hits: The Record: Their Greatest Hits: The Record is the career retrospective greatest hits album by the Bee Gees, released on UTV Records and Polydor in November 2001 as HDCD. The album includes 40 tracks spanning over 35 years of music. Four of the songs were new recordings of classic Gibb compositions originally recorded by other artists, including "Emotion" (Samantha Sang), "Heartbreaker" (Dionne Warwick), "Islands in the Stream" (Kenny Rogers and Dolly Parton), and "Immortality" (Celine Dion). It also features the Barry Gibb duet with Barbra Streisand, "Guilty", which originally appeared on Streisand's 1980 album of the same name. It is currently out of print and has been supplanted by another compilation, "The Ultimate Bee Gees".
Document 4: 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.
Document 5: 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 6: Robin Gibb (EP): Robin Gibb is the first EP released by British singer-songwriter Robin Gibb, released in 1985 on Amiga Records only in Germany.
Document 7: 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 8: The Solo Collection: The Solo Collection is a box set detailing the solo career of Freddie Mercury; it includes the material Mercury recorded before joining up with Queen, up through the 1993 No More Brothers remixes. Mercury's singles and two studio albums are included, as well as a disc of instrumentals, numerous rare tracks, and a set of interviews conducted by David Wigg. Also included are two DVDs: a collection of music videos, and a documentary covering Mercury's life.
Document 9: Mythology (Bee Gees album): Mythology is a box set compilation of recordings by the Gibb Brothers, mostly performed as the Bee Gees, arranged in a four disc set each highlighting a Gibb brother. Barry and Robin chose their own songs (presumably their personal favourites), with Maurice's songs selected by his widow Yvonne and Andy's songs selected by his daughter Peta. Several U.S. and U.K. hits are absent from this collection including "Lonely Days", "How Can You Mend a Broken Heart", "You Should Be Dancing", "Nights on Broadway", "World" and "One".
Document 10: 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 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: 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 13: 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 14: 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 15: 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.
ground_truth: Barry and Maurice Gibb