Question: Who is the White Nights director's sibling?

full_context: Document 1: Yamata: Yamata is a 1919 Hungarian silent drama film directed by Alexander Korda and starring Emil Fenyvessy, Ila Lóth and Gábor Rajnay. The film was made for the state-owned Hungarian film industry during the Hungarian Soviet Republic, and concerns a black slave's revolt against his master. The film's apparent political leftism, along with that of "Ave Caesar!" (1919), led to Korda's arrest once the Soviet Republic collapsed and he fled Hungary in 1919 during the White Terror.
Document 2: Men of Tomorrow: Men of Tomorrow is a 1932 British drama film, directed by Zoltan Korda and Leontine Sagan, produced by Alexander Korda and written by Anthony Gibbs and Arthur Wimperis. It stars Maurice Braddell, Joan Gardner and Emlyn Williams and features Robert Donat's movie debut.
Document 3: Men of America: Men of America is a 1932 American Pre-Code Western film directed by Ralph Ince and written by Samuel Ornitz and Jack Jungmeyer. The film stars William Boyd, Charles "Chic" Sale, Dorothy Wilson, Ralph Ince and Henry Armetta. The film was released on November 25, 1932, by RKO Pictures.
Document 4: The White Heather: The White Heather is a lost 1919 American silent drama film directed by Maurice Tourneur and starring Holmes Herbert, Ben Alexander and Ralph Graves. It was based on an 1897 play of the same title by Cecil Raleigh and Henry Hamilton. The future matinee idol John Gilbert appeared in a supporting part.
Document 5: White Nights (1916 film): White Nights (Hungarian: Fehér éjszakák) is a 1916 Hungarian silent drama film directed by Alexander Korda and starring Lili Berky, Kálmán Körmendy and György Kürthy. It was based on the play "Fédora" by Victorien Sardou and is sometimes known by the alternative title Fédora. It was Korda's first film for the Corvin Film studio. It was a major success and was one of the first Hungarian films to be exported to other countries.
Document 6: Faun (film): Faun is a 1918 Hungarian silent drama film directed by Alexander Korda and starring Gábor Rajnay, Dezsõ Gyárfás and Artúr Somlay. It was based on a play by Edward Knoblock.
Document 7: The Dawn of a Tomorrow (1915 film): The Dawn of a Tomorrow is a 1915 American silent film starring Mary Pickford, produced by Adolph Zukor's Famous Players Film Company and directed by James Kirkwood. It is based on a 1909 stage play starring Eleanor Robson Belmont, her last stage role. This film was rereleased by Paramount in 1919 under their "Success-Series" banner and a copy survives in Sweden today. The story was remade in 1924 again as "The Dawn of a Tomorrow" with Jacqueline Logan in the lead.
Document 8: Things to Come: Things to Come (also known in promotional material as H. G. Wells' Things to Come) is a 1936 British black-and-white science fiction film from United Artists, produced by Alexander Korda, directed by William Cameron Menzies, and written by H. G. Wells. The film stars Raymond Massey, Ralph Richardson, Cedric Hardwicke, Pearl Argyle, and Margaretta Scott.
Document 9: Men of Chance: Men of Chance is a 1931 American pre-Code drama film directed by George Archainbaud, starring Ricardo Cortez, Mary Astor, and John Halliday.
Document 10: Tales of the Typewriter: Tales of the Typewriter (Hungarian: Mesék az írógépröl) is a 1916 Hungarian silent drama film directed by Alexander Korda and starring Lili Berky, Jenő Janovics and György Kürthy. It was based on a 1905 novel by István Szomaházy.
Document 11: María Corda: She began her acting career in the theatres of Budapest in the early days of World War I and soon after the break-up of Austria-Hungary she also began to work in the film industry. Her first role was in "Se ki, se be" in 1919, directed by the Hungarian director, Korda Sandor, who would come to be known as Alexander Korda. She married Sandor, who was then the leading director in Hungary's fledgling film industry, in 1919. He featured her in three films that year "White Rose" ("Fehér rózsa"), "Ave Caesar!" and "Number 111" ("A 111-es") all of which he directed.
Document 12: Harrison and Barrison: Harrison and Barrison (Hungarian: Harrison és Barrison) is a 1917 Hungarian silent comedy film directed by Alexander Korda and starring Márton Rátkai, Dezsõ Gyárfás and Nusi Somogyi. Korda broke from his previous practice of adapting literary works, to direct an original screenplay. The film's style is a madcap one, which relied on the talents of its two stars Rátkai and Gyárfás who were popular comedians. It was Korda's most famous Hungarian film, better known than his literary adaptions. Korda himself considered the film his best work of the period.
Document 13: The Daredevil Men: The Daredevil Men is a 1972 British short subject detailing the activities of stunt performers and stunt arrangers featuring Tom Adams.
Document 14: The Man from Blankley's: The Man from Blankley's is a lost 1930 American pre-Code comedy film, directed by Alfred E. Green. It starred John Barrymore and Loretta Young. The film was based on the 1903 play by Thomas Anstey Guthrie, writing under the pseudonym "F. Anstey". The film was Barrymore's second feature length all-talking film. A previous silent film version of Anstey's play by Paramount Pictures appeared in 1920 as "The Fourteenth Man" starring Robert Warwick. That version is also lost.
Document 15: Number 111 (1919 film): Number 111 (Hungarian: A 111-es) is a 1919 Hungarian silent thriller film directed by Alexander Korda and starring Gábor Rajnay, María Corda and Gyula Bartos. The film was based on a novel by Jenő Heltai. It was Korda's final Hungarian film before he went into exile in Austria during the White Terror. The film was remade in 1938.
ground_truth: Zoltan Korda
sub_queries: White Nights >> director Answer: Alexander Korda
Alexander Korda >> sibling Answer: Zoltan Korda