Question: what is the nationality of the composer of String Quartet No. 7 ?

Context articles: Orford String Quartet
String Quartets (Schoenberg)
Ezequiel Viñao
Antonín Dvořák
Hollywood String Quartet
String Quartet No. 6 (Bartók)
Jasper String Quartet
Quartets (Fred Frith album)
String Quartet No. 7 (Dvořák)
Vitamin String Quartet

The Orford String Quartet was a Canadian string quartet active from 1965 through 1991.
 They came to be the leading string quartet in Canada, and one of the finest in the world.
 "For 26 years, the Orford String Quartet was the best of its breed in Canada."
The Austrian composer Arnold Schoenberg published four string quartets, distributed over his lifetime.
 These were the String Quartet No. 1 in D minor, Op. 7 (1905), String Quartet No. 2 in F sharp minor, Op. 10 (1908), String Quartet No. 3, Op. 30 (1927), and the String Quartet No. 4, Op. 37 (1936).
Ezequiel Viñao (born 1960 in Buenos Aires) is an Argentine-American composer.
 He emigrated to the United States in 1980 and studied at the Juilliard School.
 His compositions include "La Noche de las Noches" (1989) for string quartet and electronics, which won First Prize at UNESCO's Latin-American Rostrum of Composers in 1993; six "Études" (1993) for piano solo, which were awarded a Kennedy Center Friedheim Award in 1995; a second string quartet "The Loss and the Silence" (2004), commissioned by the Juilliard String Quartet; "The Wanderer" (2005) for a cappella voices, commissioned by Chanticleer and Chicago a cappella, and "Sirocco Dust" (2009), commissioned by the Library of Congress for the St. Lawrence String Quartet.
 He currently resides in New York City.
Antonín Leopold Dvořák ( ; ] ; 8 September 1841 – 1 May 1904) was a Czech composer.
 After Bedřich Smetana, he was the second Czech composer to achieve worldwide recognition.
 Following Smetana's nationalist example, Dvořák frequently employed aspects, specifically rhythms, of the folk music of Moravia and his native Bohemia.
 Dvořák's own style has been described as "the fullest recreation of a national idiom with that of the symphonic tradition, absorbing folk influences and finding effective ways of using them."
The Hollywood String Quartet (HSQ) was an American string quartet founded by violinist/conductor Felix Slatkin and his wife cellist Eleanor Aller.
 The Hollywood String Quartet is considered to be the first American-born and trained classical music chamber group to make an international impact, mainly through its landmark recordings.
 These recordings have long been regarded as among the most outstanding recorded performances of the string quartet repertoire.
The String Quartet No. 6, Sz.
 114, BB 119, was the final string quartet that Béla Bartók wrote before his death.
 It was begun in August 1939 in Saanen, Switzerland, where Bartók was a guest of his patron, the conductor Paul Sacher.
 Shortly after he completed the Divertimento for String Orchestra on the 17th, he started on a commission for his friend, the violinist Zoltán Székely.
 Székely was acting as intermediary for the "New Hungarian Quartet", who had given the Budapest premiere of the String Quartet No. 5.
 With the outbreak of World War II and his mother's illness, Bartók returned to Budapest, where the quartet was finished in November.
 After his mother's death, Bartók decided to leave with his family for the United States.
 Due to the difficulties of the war, communication between Bartók and Székely was difficult, and the quartet was not premiered until 20 January 1941, when the Kolisch Quartet, to whom the work is dedicated, gave its premiere at the Town Hall in New York City.
The Jasper String Quartet is a professional string quartet based in Philadelphia, Pennsylvania.
 Currently the Ensemble in Residence at Temple University's Center for Gifted Young Musicians, the quartet was previously the Quartet in Residence at Oberlin Conservatory (from 2010-2012).
 Formed in 2004 while its members were in school at Oberlin Conservatory, the quartet completed string quartet master's programs at Rice University (2006-2008) and Yale University (2008-2010).
 The group's primary mentors are James Dunham, Norman Fischer and the Tokyo String Quartet.
 In 2010, they joined the roster of Astral Artists.
Quartets is a 1994 studio album by English guitarist, composer and improvisor Fred Frith.
 It consists of two compositions by Frith, "Lelekovice, String Quartet #1", performed by the Violet Wires String Quartet, and "The As Usual Dance Towards the Other Flight to What is Not", performed by an electric guitar quartet.
 Frith performs with the guitar quartet, but not with the string quartet.
Antonín Dvořák finished the composition of his String Quartet No. 7 in a minor, Op.
 16, (B. 45) on 24/9/1874, having probably started it on or around the 14th of that month.
Vitamin String Quartet (VSQ) is a musical group from Los Angeles, California, that is widely known for its series of tribute albums to rock and pop acts.
 Their albums are released through Vitamin Records and primarily performed by a string quartet, though other instruments have been used.
 "Vitamin String Quartet is about applying rock n' roll attitude to classical technique," says Tom Tally, a violist and arranger who has performed on and produced over fifty Vitamin String Quartet albums.