Question: What do Anthony Green and Serj Tankian have in common?

full_context: Document 1: Glaring Through Oblivion: Glaring Through Oblivion is a 2011 book of poetry written by Serj Tankian, the Armenian-American lead singer of the band System of a Down. It is his second book of poetry, after "Cool Gardens" (2002). "Glaring Through Oblivion" was published by HarperCollins Publishers and printed in China, and released on March 22, 2011.
Document 2: Elect the Dead: Elect the Dead is the debut album by rock musician Serj Tankian, lead singer and founding member of Armenian-American metal quartet System of a Down. It was released on October 22, 2007. Alongside Tankian appears Armenian-American coloratura Ani Maldjian, drummers John Dolmayan from System of a Down and B. Brain Mantia of Primus and Guns N' Roses, Dan Monti on guitars, as well as a string section featuring Antonio Pontarelli.
Document 3: Cool Gardens: Cool Gardens is a poetry book by the lead singer of the band System of a Down, Serj Tankian. It was published by MTV Books and was released on October 1, 2002. It is a collection of seven to eight years of Tankian's reflections on life, and features artwork by fellow Angeleno, Sako Shahinian. The poetry, like the songs of System of a Down, consists of a reflection of societies and people's wrongs. It portrays what people do to themselves and the control others try to hold over them.
Document 4: Beautiful Things (album): Beautiful Things is the second studio album by Circa Survive's vocalist, Anthony Green. It was released on January 17, 2012, and peaked at No. 27 on the Billboard 200 chart.
Document 5: High and Driving: High and Driving is a side project formed by Anthony Green, the current vocalist of Circa Survive, and Tim Arnold, the then-drummer of Days Away and current drummer of Good Old War. Anthony Green plays every instrument aside from drums. "High and Driving", a four-track EP, is the duo's only release.
Document 6: Anthony Green (musician): Anthony Green (born April 15, 1982) is an American musician from Doylestown, Pennsylvania. He is currently the lead singer of Circa Survive and Saosin, while also maintaining a solo career. He was previously in the bands The Sound of Animals Fighting, Audience of One, Jeer at Rome, High and Driving, and Zolof the Rock and Roll Destroyer. Green is known for his high tenor vocal range.
Document 7: Serj Tankian: Serj Tankian (Western Armenian: Սերժ Թանկեան , ] ; born August 21, 1967) is a Lebanese-born Armenian-American singer-songwriter, composer, multi-instrumentalist, record producer, poet, and political activist with Armenian descent. He is best known as the lead vocalist, songwriter, keyboardist, and occasional live rhythm guitarist of the metal band System of a Down, formed in 1994.
Document 8: System of a Down discography: System of a Down is an American rock band formed by musicians of Armenian origin: vocalist Serj Tankian, guitarist Daron Malakian, bassist Shavo Odadjian, and drummer John Dolmayan in the mid-1990s. They have released five studio albums, 16 singles, and 11 music videos. By the end of 1997, the group had signed to American Recordings, then distributed as Columbia Records. The following year, they released their eponymous debut album, which peaked at #124 on the United States' "Billboard" 200 and #103 on the United Kingdom's UK Albums Chart; it was certified platinum two years later by the Recording Industry Association of America (RIAA), and gold by Canadian Recording Industry Association (CRIA). Their eponymous debut album produced a single for the song "Sugar", which reached the top 30 on the "Billboard" mainstream rock songs and alternative songs charts. Their follow-up album, "Toxicity" (2001), topped the US and Canadian charts, and also reached the top 10 in Australia, Finland, and New Zealand. The album was certified triple platinum in its home country, and triple platinum in Australia by the Australian Recording Industry Association (ARIA), as well as double platinum by CRIA in Canada. "Toxicity" produced singles for the title track, "Chop Suey!", and "Aerials". The last of these peaked at number one on the "Billboard" Mainstream Rock Songs and Alternative Songs charts.
Document 9: Avalon (Anthony Green album): Avalon is the debut solo album by current Saosin and current Circa Survive, vocalist Anthony Green. It was released August 5, 2008 on Photo Finish Records, with a US tour to coincide with its release. Keith Goodwin, Tim Arnold, and Dan Schwartz (also known as the band Good Old War) have guest appearances on this record. The album leaked in its entirety on August 1, 2008. Anthony Green's Avalon is being made available on vinyl LP. The package includes the limited Vinyl LP and Digital Remix CD of Avalon, remixes created by Colin Frangicetto of Circa Survive.
Document 10: System of a Down: System of a Down, sometimes shortened to System and abbreviated as SOAD, is an Armenian-American heavy metal band from Glendale, California, formed in 1994. The band currently consists of Serj Tankian (lead vocals, keyboards), Daron Malakian (vocals, guitar), Shavo Odadjian (bass, backing vocals) and John Dolmayan (drums).
Document 11: Serart: Serart is a collaboration album by two international Armenian musicians: Serj Tankian ("Ser-"), lead singer of System of a Down, and folk multi-instrumentalist Arto Tunçboyacıyan ("-art"). It was the first release on Tankian's own label, Serjical Strike Records.
Document 12: Circa Survive: Circa Survive is an American rock band from the Philadelphia suburb of Doylestown, formed in 2004. The band, led by Anthony Green, consists of former members from Saosin, This Day Forward, and Taken.
Document 13: Daron Malakian: Daron Vartan Malakian (Armenian: Տարօն/Տարոն Վարդան Մալաքեան, born July 18, 1975) is an Armenian–American singer-songwriter, multi-instrumentalist, and record producer. He is best known as the guitarist, songwriter and second vocalist of the rock band System of a Down and as the lead vocalist, lead guitarist and songwriter of the band Scars on Broadway. Like the rest of the Hollywood-based band System of a Down, he is of Armenian ancestry, but he is the only member to have been born in the United States. Daron Malakian is known for his distinctive playing and is ranked 40th in Loudwire's list of "Top 50 Hard Rock + Metal Guitarists Of All Time" and #11 in MusicRadar's poll, "The 20 Greatest Metal Guitarists Ever". He is placed 30th in Guitar World's List of The 100 Greatest Heavy Metal Guitarists of All Time.
Document 14: Caleb Green: Master sergeant Caleb B. Green III is a solo vocalist with the United States Army Band. An accomplished performer, particularly of the US national anthem, Green is often called upon to sing at important sporting events, diplomatic functions and military ceremonies. His most notable anthem performance was at the at the Lincoln Memorial in Washington, D.C.. Prior to this his most notable outing was onstage in the TNT production "Christmas in Washington 2008", in which he sang "O Holy Night".
Document 15: Saosin: Saosin is an American rock band from Orange County, California, United States. The band was formed in 2003 and recorded its first EP, "Translating the Name", that same year original vocalist Anthony Green left Saosin due to personal reasons. In 2004, Cove Reber replaced Green as vocalist after auditioning for the role. The group recorded its self titled debut album which was released on Capitol Records on September 26, 2006. Their second studio album, "In Search of Solid Ground", was released on September 8, 2009 on Virgin and contains three re-recorded tracks off of "The Grey EP". Reber departed from the band in 2010 and subsequently went on a three-year hiatus. In 2013, the band reformed with all original members, except Zach, and began touring. They released their third studio album and their first studio album, "Along the Shadow", with original vocalist Anthony Green on May 20, 2016 through Epitaph Records. It is also the album that marks the final feature lead guitarist Justin Shekoski.
ground_truth: singer