The Snowman is a children's picture book without words by English author Raymond Briggs, first published in 1978 by Hamish Hamilton in the United Kingdom, and published by Random House in the United States in November of the same year.
 In the UK, it was the runner up for the Kate Greenaway Medal from the Library Association, recognising the year's best children's book illustration by a British writer.
Odette Tchernine is the author of several books on the Abominable Snowman or Yeti, such as "In Pursuit of the Abominable Snowman", Taplinger Publishing, 1971.
 She worked heavily in this area at least from the 1950s through the 1970s.
 Before "In Pursuit", she published "The Snowman and Company".
 Her research has taken her all over the world and she has consulted with numerous individuals in this field of study.
Brian Tse (謝立文) is the author of the Hong Kong children comic, "McMug and McDull" series.
 He is one of the two creators (another is Alice Mak, his colleague-turned-wife) of the cartoon characters McMug and McDull.
 His wife is responsible for the illustration.
 His other works include ""The Excreman"" (a "serious" parody of the famous English cartoon, ""The Snowman""), ""The Beautiful Loser"", ""Pig Has Come"", and ""Over the Rainbow"".
Peter Hannan (born August 13, 1954) is an American animator, singer-songwriter, author, illustrator, producer, artist, and entrepreneur.
 Hannan is the creator, executive producer, and show runner of the Nickelodeon series "CatDog".
 He also wrote and sang the "CatDog" theme song.
 He has created and developed properties for numerous studios.
 He works as a character designer and writes for various other animated shows.
 He created a web series called "Really Freaking Embarrassing," single-panel cartoons called "The Adventures of a Huge Mouth" that ran in independent newspapers throughout the U.S., and writes and illustrates books, including "Petlandia, My Big Mouth: 10 Songs I Wrote That Almost Got Me Killed, The Greatest Snowman in the World," "Super Goofballs, Sillyville or Bust," "Escape from Camp Wannabarf," "School After Dark: Lessons in Lunacy," and "The Battle of Sillyville: Live Silly or Die!"
 He has written and illustrated newspaper and magazine pieces with titles like "The Incredible Shrinking Christmas" and "The Good, the Bad, and the Irish."
 He co-founded the company "FutureVision", which produced a TV concert series featuring blues legends Muddy Waters, Albert King, Buddy Guy & Junior Wells, Bobby Bland, Otis Rush, Blind John Davis, and others.
 He has taught, lectured, and led art, writing, animation, and creativity workshops for pre-school through college students.
 He has worked as a graphic designer and art director and done illustrations for magazines, newspapers, and advertising.
 He exhibits paintings, illustrations, and cartoons.
Colin Edwards (1924–1994) was a radio journalist and documentary film maker.
 He was also an actor, author, university lecturer, Plaid Cymru activist and founder of the American CADW (Committee to Aid the Defence of Wales).
 An expert on middle eastern affairs, and advisor to the United Nations and policy think-tanks, he was also interested in the arts, anthropology and science: his broadcasts included comment on the Irish theatre, European witchcraft, Congo tribal customs, chemical pesticides, the Abominable Snowman and Vernon Watkins.
Milt Machlin (June 26, 1924 – April 3, 2004) was an American journalist, author and adventurer.
 He is best known for coining the phrases "Bermuda Triangle" and "Abominable Snowman," as well as his expedition to find scion Michael Rockefeller, who disappeared in New Guinea in 1961.
Robert Lindsey (born 1935) is a journalist and author of several true crime books, including "The Falcon and the Snowman: A True Story of Friendship and Espionage" (1980), the story of Christopher John Boyce and Andrew Daulton Lee, who were both convicted of selling information to the Soviets. ""
 (1983) followed, a chronology of Christopher Boyce's escape from Federal prison and subsequent bank robbing spree.
"The Snowman" is a literary fairy tale by Hans Christian Andersen about a snowman who falls in love with a stove.
 It was published by C.A. Reitzel in Copenhagen as "Sneemanden" on 2 March 1861.
 Andersen biographer Jackie Wullschlager describes the tale as a lyrical and poignant complement to Andersen's "The Fir-Tree" of December 1844.
"The Fir-Tree" (Danish: "Grantræet") is a literary fairy tale by the Danish poet and author Hans Christian Andersen (1805–1875).
 The tale is about a fir tree so anxious to grow up, so anxious for greater things, that he cannot appreciate living in the moment.
 The tale was first published 21 December 1844 with "The Snow Queen", in Copenhagen, Denmark, by C.A. Reitzel.
 One scholar (Andersen biographer Jackie Wullschlager) indicates that "The Fir-Tree" was the first of Andersen's fairy tales to express a deep pessimism.
Raymond Redvers Briggs, CBE (born 18 January 1934) is an English illustrator, cartoonist, graphic novelist and author who has achieved critical and popular success among adults and children.
 He is best known in Britain for his story "The Snowman", a book without words whose cartoon adaptation is televised and whose musical adaptation is staged every Christmas.

Question: Who was the author of both The Snowman and The Fir-Tree?
Answer: Hans Christian Andersen