Question: When was the owner of the publisher of Interstellar Pig formed?

full_context: Document 1: Boston: The city's growing Latino population has given rise to a number of local and regional Spanish-language newspapers. These include El Planeta (owned by the former publisher of The Boston Phoenix), El Mundo, and La Semana. Siglo21, with its main offices in nearby Lawrence, is also widely distributed.
Document 2: Random House: Penguin Random House Grupo Editorial is Random House's Spanish-language division, targeting markets in Spain and South and Central America. It is headquartered in Barcelona with locations in Argentina, Chile, Colombia, Mexico, Uruguay, and the United States. From 2001 until November 2012, it was a joint venture with Italian publisher Mondadori (Random House Mondadori). Upon Bertelsmann's acquisition of Mondadori's stake in the JV, the name was kept temporarily four months. Some authors published by Penguin Random House Grupo Editorial include Dr. César Lozano, Yordi Rosado, Dr. Nancy Alvarez and Alberto Sardiñas.
Document 3: The Green Futures of Tycho: The Green Futures of Tycho is a 1981 science fiction novel for young audiences by William Sleator. The book explores the effect of excessive parent expectations on the future of their children.
Document 4: Cemex: Lorenzo Zambrano was the chairman and chief executive officer until his death on May 21, 2014. About one-third of the company's sales come from its Mexico operations, a quarter from its plants in the U.S., 15% from Spain, and smaller percentages from its plants around the world.
Document 5: Miami: Several large companies are headquartered in or around Miami, including but not limited to: Akerman Senterfitt, Alienware, Arquitectonica, Arrow Air, Bacardi, Benihana, Brightstar Corporation, Burger King, Celebrity Cruises, Carnival Corporation, Carnival Cruise Lines, Crispin Porter + Bogusky, Duany Plater-Zyberk & Company, Espírito Santo Financial Group, Fizber.com, Greenberg Traurig, Holland & Knight, Inktel Direct, Interval International, Lennar, Navarro Discount Pharmacies, Norwegian Cruise Lines, Oceania Cruises, Perry Ellis International, RCTV International, Royal Caribbean Cruise Lines, Ryder Systems, Seabourn Cruise Line, Sedano's, Telefónica USA, UniMÁS, Telemundo, Univision, U.S. Century Bank, Vector Group and World Fuel Services. Because of its proximity to Latin America, Miami serves as the headquarters of Latin American operations for more than 1400 multinational corporations, including AIG, American Airlines, Cisco, Disney, Exxon, FedEx, Kraft Foods, LEO Pharma Americas, Microsoft, Yahoo, Oracle, SBC Communications, Sony, Symantec, Visa International, and Wal-Mart.
Document 6: W. W. Norton & Company: W.W. Norton & Company is an American publishing company based in New York City. It has been owned wholly by its employees since the early 1960s. The company is known for its ``Norton Anthologies ''(particularly The Norton Anthology of English Literature) and its texts in the Norton Critical Editions series, the latter of which are frequently assigned in university literature courses.
Document 7: Bantam Books: Bantam Books is an American publishing house owned entirely by parent company Random House, a subsidiary of Penguin Random House; it is an imprint of the Random House Publishing Group. It was formed in 1945 by Walter B. Pitkin, Jr., Sidney B. Kramer, and Ian and Betty Ballantine, with funding from Grosset & Dunlap and Curtis Publishing Company. It has since been purchased several times by companies including National General, Carl Lindner's American Financial and, most recently, Bertelsmann; it became part of Random House in 1998, when Bertelsmann purchased it to form Bantam Doubleday Dell. It began as a mass market publisher, mostly of reprints of hardcover books, with some original paperbacks as well. It expanded into both trade paperback and hardcover books, including original works, often reprinted in house as mass-market editions.
Document 8: Interstellar Pig: Interstellar Pig, published in 1984 by Bantam Books, is a science fiction novel for young adults written by William Sleator. It was listed as an ALA Notable Book, a SLJ Best Book of the Year, and a Junior Literary Guild Selection.
Document 9: Department store: The first department store in Spain was Almacenes el Siglo opened in October 1881 in Barcelona. Following the 2002 closure by the Australian group Partridges of their SEPU (Sociedad Española de Precios Unicos) department store chain, which was one of Spain's oldest, the market is now dominated by El Corte Inglés, founded in 1934 as a drapery store. El Corte Inglés stores tend to be vast buildings, selling a very broad range of products and the group also controls a number of other retail formats including supermarket chain 'Supercor' and hypermarket chain 'Hipercor'. Other competitors such as 'Simago' and 'Galerías Preciados' closed in the 1990s, however El Corte Inglés, faces major competition from French discount operators such as Carrefour and Auchan.
Document 10: Parasite Pig: Parasite Pig is a young adult science fiction novel written by William Sleator. It is the sequel to the 1984 book "Interstellar Pig".
Document 11: William Sleator: William Warner Sleator III (February 13, 1945 – August 3, 2011), known as William Sleator, was an American science fiction author who wrote primarily young adult novels but also wrote for younger readers. His books typically deal with adolescents coming across a peculiar phenomenon related to an element of theoretical science, then trying to deal with the situation. The theme of family relationships, especially between siblings, is frequently intertwined with the science fiction plotline.
Document 12: Manning Publications: Manning Publications is an American publisher established by Lee Fitzpatrick and Marjan Bace that publishes books on computer technology topics, with a particular focus on web development. Their distinctive brand features illustrations from the 1805 edition of Sylvain Maréchal's four-volume compendium of regional dress customs on the covers of many of their books.
Document 13: Guinness World Records: Guinness Superlatives (later Guinness World Records) Limited was formed in 1954 to publish the first book. Sterling Publishing owned the rights to the Guinness book in the US for decades. The group was owned by Guinness PLC and subsequently Diageo until 2001, when it was purchased by Gullane Entertainment. Gullane was itself purchased by HIT Entertainment in 2002. In 2006, Apax Partners purchased HiT and subsequently sold Guinness World Records in early 2008 to the Jim Pattison Group, the parent company of Ripley Entertainment, which is licensed to operate Guinness World Records' Attractions. With offices in New York City and Tokyo, Guinness World Records' global headquarters remain in London, while its museum attractions are based at Ripley headquarters in Orlando, Florida, US.
Document 14: Dover Publications: Dover Publications, also known as Dover Books, is an American book publisher founded in 1941 by Hayward Cirker and his wife, Blanche. It primarily publishes reissues, books no longer published by their original publishers. These are often, but not always, books in the public domain. The original published editions may be scarce or historically significant. Dover republishes these books, making them available at a significantly reduced cost.
Document 15: The Boy Who Reversed Himself: The Boy Who Reversed Himself (1986) is a science fiction novel by William Sleator. The novel deals with an exploration into other dimensions, and provides a journey into the world beyond our own.
ground_truth: 2001
sub_queries: Who published Interstellar Pig? Answer: Bantam Books
Bantam Books >> owned by Answer: Random House
Which year witnessed the formation of Random House ? Answer: 2001