Question: Don Dokken and Roy Khan, have which mutual occupation?

Context paragraphs:
The Fourth Legacy: The Fourth Legacy is the fourth full-length album by power metal band Kamelot.  It was released in 1999 by Noise Records/Modern Music.  It was the first album to credit vocalist Roy Khan as a writer on all tracks, establishing him as the main songwriter of the band together with founder and guitarist Thomas Youngblood.

Roy Khan: Roy Sætre Khantatat (born March 12, 1970), is a Norwegian singer-songwriter.  Commonly known as Roy Khan or simply Khan, he was the lead vocalist for the symphonic power metal band Kamelot from 1997 to his departure in 2011.  He co-wrote most of Kamelot's songs with the band's guitarist and founder Thomas Youngblood during his tenure.  Prior to joining Kamelot, Khan was lead singer for the Norwegian progressive metal band Conception from 1991 until 1997 when they disbanded.

Begum Om Habibeh Aga Khan: Begum Om Habibeh Aga Khan (15 February 1906 – 1 July 2000) was the fourth and last wife of Sir Sultan Muhammad Shah, Aga Khan III.  The couple married thirteen months after the Aga Khan III and his third wife were divorced by mutual consent.  The Begum was well known for her generosity towards and compassion for the impoverished and the elderly.  Her Egyptian Om Habibeh Foundation worked towards the alleviation of poverty and the improvement of quality of life in the area surrounding Aswan, Egypt, and in Le Cannet she established a retirement home.  She was particularly interested in women’s issues and, an accomplished artist and sculptor, she was also interested in the arts including classical music, ballet, and the opera.  The Begum died at the age of 94 in Le Cannet and was buried in the mausoleum of her husband at Aswan.

Consign to Oblivion: Consign to Oblivion is the second studio album by Dutch symphonic metal band Epica, and was released in 2005.  The song "Trois Vierges" features a guest appearance by then Kamelot vocalist Roy Khan.  The album's lyrics are inspired by the Maya civilization.  The CD was released with copy control on it.  This CD started a new collection of songs, called "A New Age Dawns".  This saga is continued on the album "Design Your Universe".

Don Dokken: Donald Maynard Dokken (born June 29, 1953) is an American heavy metal vocalist, best known for being the lead singer, occasional guitarist, and founder of the band Dokken.  He used to be known for his vibrato-laden, melodic vocal style which has made him an influential figure in American hard rock and heavy metal.  After enjoying mainstream success with Dokken, he parted ways with the band in 1988 and pursued a solo career.  His 1990 solo album, "Up from the Ashes", spawned two singles.

Siége Perilous: Siége Perilous is the third full-length album released by the power metal band Kamelot.  It was released on August 4, 1998, through Noise Records.  It is the first album with Roy Khan (ex-Conception) on vocals and Casey Grillo on drums, and also the last with the keyboard player David Pavlicko.

Roy model: The Roy model is one of the earliest works in economics on self-selection due to Arthur Roy.  The basic model considers two types of workers that choose occupation in one of two sectors.  Roy's original paper deals with workers selecting into fishing and hunting professions, where there is no uncertainty about the amount of goods (fish or rabbits) that will be caught in a given period, but fishing is more costly as it requires more skill.  The central question that Roy tries to answer in the original paper is whether the best hunters will hunt and the best fishermen will fish.  While the discussion is non-mathematical, it is observed that choices will depend on the distribution of skills, the correlation between these skills in the population, and the technology available to use these skills.

Kohali, Faisalabad: Kohali is a village of union council 47-GB of samundri of Faisalabad District in the Punjab province of Pakistan.  It is part of samundri, and located at latitude 31° 7'45.50"N and longitude 72°47'56.72"E with an altitude of 563 feet.  It was very rich and historical village before independence.  It is known for many army personnel for Pakistan like General Fahim Akhtar Khan, Brig. Muhammad Akram, Maj Basheer Ahmed Khan and his two sons.  Brig Akram is the first Pakistani who visited Antarctica and anchored Pakistan flag there.  They have done many awesome or worth praising service for their native village.  Rana Mukhtar Ahmad Khan Chairman is Great Person And Political Personality of Kohali.  Also Muhammad Aslam Anjum is the most influential personality of Kohali.  His son Awais Anjum has remarkable contribution to the Nation's defense industry.  Most of the population of this village is Muslim .  There are four mosques and one Imambargah in the village.  More influential tribes and clans are Rajput, Jat, Arian, etc.  Main occupation of the people are cultivation.  This village is located about 10 km from Gojra and about 29 km from Samundri.

Biswajit Roy Chowdhury: Pandit Biswajit Roy Chowdhury was born in 1956, in Deogarh, Chowdhury was initiated into music by his father Shri Ranajit Roy Chowdhary, who was teacher of chemistry by profession but, more importantly, a serious Sarod player trained under the Late Ustad Hafiz Ali Khan and others.  In 1978, Roy Chowdhury's talents were spotted by the Maestro Ustad Amjad Ali Khan accepting him as a disciple.  A turning point came when Pandit Mallikarjun Mansur took an interest in young Roy Chowdhury's quest in 1982.  The union of an instrument player with Pandit Mansur set the journey on the path of fulfilling this quest.  Biswajit Roy Chowdhary’s tutelage with Pandit Mallikarjun Mansur was formalized in a gandhabandhan ceremony in 1985 and the intensive guidance and training lasted till the demise of the guru in 1992.  He is perhaps the only Sarod player who plays the coveted compositions from the Jaipur-Atrauli tradition.

Kamelot: Kamelot is an American power metal band from Tampa, Florida, formed by Thomas Youngblood and Richard Warner in 1991.  The Norwegian vocalist Roy Khan joined for the album "Siége Perilous", and shared songwriting credit with Youngblood until his departure in April 2011.  On June 22, 2012, Youngblood announced on their website that their new vocalist is the Swedish singer Tommy Karevik, who was first featured on Kamelot's album "Silverthorn" as main vocalist, co-songwriter and lyricist.

Supporting paragraphs: Don Dokken Roy Khan
Answer: singer