Question: What insturument type did Dickie Peterson and Ely Buendia have in common?

full_context: Document 1: Pete Best: Randolph Peter "Pete" Best (born Randolph Peter Scanland, 24 November 1941) is an English musician, principally known as an original member and first drummer of the Beatles, from 1960 to 1962. He has been referred to as the Fifth Beatle.
Document 2: Rivermaya: Rivermaya is a Filipino rock band. Formed in 1994, it is one of several bands who spearheaded the 1990s Philippine alternative rock explosion. Rivermaya is currently composed of original members Mark Escueta and Nathan Azarcon, together with Mike Elgar and Ryan Peralta. Former original members include Rico Blanco, who had been the original songwriter of the band and vocalist Bamboo Mañalac, who later formed the band Bamboo and later went on his solo career. Rivermaya is listed as the twentieth biggest-selling artists/act in the Philippines as of present.
Document 3: Ely Buendia: Eleandre "Ely" Basiño Buendia (born November 2, 1970) is a Filipino musician, writer and director who gained fame as guitarist, songwriter and lead vocalist of the popular Filipino rock band Eraserheads. His compositions gained success and critical acclaim, topping various music charts, and are now considered classics. Widely regarded as one of the most respected music icons in the country, he currently performs as guitarist and lead vocalist for Pupil, The Oktaves and Apartel.
Document 4: The Beast Is Back: The Beast Is Back is the seventh album by a newly reformed Blue Cheer, 13 years after their previous album, "Oh! Pleasant Hope" (1971). It contains re-recorded versions of some of the band's most popular songs from their late-1960s heyday as well as new material. The album features founding members Dickie Peterson and Paul Whaley. Original guitarist Leigh Stephens did not participate in the reunion.
Document 5: Dickie Peterson: Richard Allan Peterson (September 12, 1946 – October 12, 2009) was an American musician, best known as the bassist and lead singer for Blue Cheer. He also recorded two solo albums: "Child of the Darkness" and "Tramp".
Document 6: Perfecto de Castro: Perfecto "Perf" de Castro (born August 14) is a multi-awarded Filipino musician, currently focusing on Classical and Flamenco music played on the Ten-string guitar, and now widely regarded being the best guitarist in the country. but perhaps best known for having been a celebrated fixture in the Philippine alternative rock scene during the 1990s. During the course of that decade, he was one of the original members of the alternative rock band Rivermaya, founded the band Triaxis, and also collaborated with the seminal Filipino rapper Francis Magalona and Filipino hard rock band Wolfgang.
Document 7: Eric Peterson (musician): Eric Peterson (born May 14, 1964) is an American guitarist. He is best known as the only constant member of the US thrash metal band Testament. Peterson has also formed a side project black metal band called Dragonlord, in which he plays guitar and also sings. In Testament, Peterson was originally a rhythm guitarist while Alex Skolnick handled all lead work. More recently though, Peterson plays leads along with Skolnick.
Document 8: Dave Peters: Dave Peters is an American musician. He was the original guitarist for the band Eighteen Visions, guitarist for the band Throwdown, and, as of 2002, the vocalist for Throwdown. He did guest vocals for the song "Unleash" by groove metal band Soulfly, for the song "Feel as Though You Could" by Demon Hunter, and the song "Despair" for Living Sacrifice. He is straight edge.
Document 9: The Oktaves: The Oktaves is a Filipino rock supergroup formed in 2011 consisting of Ely Buendia (of Eraserheads, Pupil, and The Mongols), Nitoy Adriano (of The Jerks), and Hilera members Chris Padilla, Ivan Garcia, and Bobby Padilla. The band was named after the music term "Octave", which is the interval between one musical pitch and another with half or double its frequency. This principle also mirrors the age and experience of its band members spread through three decades of Filipino music, whereas Adriano began during the 1970s, while Buendia began during the 1980s, and the rest of the younger band members began during the 1990s. Buendia also collaborated with The Jerks and Hilera on different independent projects, which also prompted him to form the band.
Document 10: Él Records: él is an English independent record label based in London that was founded by Mike Alway, later becoming a subsidiary of Cherry Red Records. Their musicians were characterized by a strong English sensibility, as well as the French influence stemming from in-house writer/producer Louis Philippe. During its original run, él received much press interest, but little sales—except in Japan, where the label became an enormous influence on J-pop acts like Cornelius and Pizzicato Five. The label closed in 1989. In 2005, it was revived as a reissue label.
Document 11: Oh! Pleasant Hope: Oh! Pleasant Hope is the sixth, and last, album by Blue Cheer until 1983's "The Beast Is Back". It features less psychedelia and hard rock and includes more folk rock elements. This is an unusual Blue Cheer album in that Dickie Peterson only sings lead on three songs. Another unusual aspect is that the song "I'm the Light" features extensive use of the sitar and synthesizer, although on the previous album "The Original Human Being" the song "Babaji (Twilight Raga)" also featured extensive use of the aforementioned instruments.
Document 12: Peter Cetera: Peter Paul Cetera ( ; born September 13, 1944) is an American singer, songwriter, and bassist best known for being an original member of the rock band Chicago (1967–1985), before launching a successful solo career. His career as a recording artist encompasses seventeen albums with Chicago and eight solo albums.
Document 13: Eraserheads: Eraserheads (sometimes stylized as ERASƎRHEADS) is a Filipino rock band formed in 1989. Consisting of Ely Buendia, Marcus Adoro, Buddy Zabala, and Raimund Marasigan, the band became one of the most successful, most influential, critically acclaimed, and significant bands in the history of Philippine music, leaving a legacy that resulted to them being the most commercially successful Filipino music artists of all time. Often dubbed as "The Beatles of the Philippines", they are credited for spearheading a second wave of Manila band invasions, paving the way for a host of Philippine alternative rock bands.
Document 14: Pete Loeffler: Pete Loeffler (born October 19, 1976) is a musician, known for his work with the Chicago-area rock band Chevelle, for which he is the lead vocalist and sole guitar player.
Document 15: Ben Deily: Ben Deily is an American musician and songwriter, most famous as one of the founders, writers and lead singers (along with Evan Dando) of the Boston-based alternative rock band The Lemonheads.
ground_truth: guitarist