Question: What is the publishing year of this children's book written and illustrated by Dr. Seuss, in which the featured characted was also part of a book "Horton Hatches the Egg"?

full_context: Document 1: Mr. Brown Can Moo! Can You?: Mr. Brown Can Moo! Can You?: Dr. Seuss's Book of Wonderful Noises! is a children's book written and illustrated by Theodor Geisel under the pen name Dr. Seuss and published by Random House in 1970.
Document 2: Seussical: Seussical is a musical by Lynn Ahrens and Stephen Flaherty based on the stories of Dr. Seuss (mainly "Horton Hears a Who!", "Horton Hatches the Egg" and "Miss Gertrude McFuzz") that debuted on Broadway in 2000. The play's story is a complex amalgamation of many of Seuss's most famous books. After a Broadway run, the production spawned two US national tours and a UK tour. It has become a beloved classic for schools, communities, and regional theatres.
Document 3: Horton Hatches the Egg (film): Horton Hatches the Egg is a ten-minute animated short film based on the book by Dr. Seuss, by Leon Schlesinger Productions in 1942, released as part of Warner Bros.' "Merrie Melodies" series. The short, which in contrast to the original children's book, was more adult-oriented and was directed by Bob Clampett. Horton was voiced by Kent Rogers along with the Peter Lorre fish, Sara Berner voiced Mayzie and the elephant bird, Frank Graham narrated, and Mel Blanc performed most of the other voices.
Document 4: Horton Hatches the Egg: Horton Hatches the Egg is a children's book written and illustrated by Theodor Geisel under the pen name Dr. Seuss and published in 1940 by Random House. The book tells the story of Horton the Elephant, who is tricked into sitting on a bird's egg while its mother, Mayzie, takes a permanent vacation to Palm Beach. Horton endures a number of hardships but persists, often stating, "I meant what I said, and I said what I meant. An elephant's faithful, one hundred percent!" Ultimately, the egg hatches, revealing an elephant-bird, a creature with a blend of Mayzie's and Horton's features.
Document 5: Heffalump: A Heffalump is a type of fictional elephant in the Winnie the Pooh stories by A. A. Milne. Heffalumps are mentioned, and only appear, in Pooh and Piglet's dreams in "Winnie-the-Pooh" (1926) and seen again in "The House at Pooh Corner" (1928). Physically, they resemble elephants; Shepard's illustration shows an Indian elephant. They are later featured in the animated television series "The New Adventures of Winnie the Pooh" (1988–1991), followed by two animated films in 2005, "Pooh's Heffalump Movie" and "Pooh's Heffalump Halloween Movie".
Document 6: Hathi: Shree. Hathi is a fictional character created by Rudyard Kipling for the Mowgli stories collected in "The Jungle Book" (1894) and "The Second Jungle Book" (1895). Hathi is a bull elephant that lives in the jungle. Kipling named him after "hāthī" (हाथी),(ہاتھی) the Hindi and Urdu word for "elephant".
Document 7: The Lorax: The Lorax is a children's book written by Dr. Seuss and first published in 1971. It chronicles the plight of the environment and the Lorax, who speaks for the trees against the Once-ler. As in most Dr. Seuss works, most of the creatures mentioned are original to the book.
Document 8: Horton the Elephant: Horton the Elephant is a fictional character from the 1940 book "Horton Hatches the Egg" and 1954 book "Horton Hears a Who!", both by Dr. Seuss. Horton is a kind, sweet-natured elephant who cares about other animals or people. Though he goes through many hardships, whether trying to keep an egg warm through storms, rough travels, and humiliating shows, or tries to save a small planet from harm, he always triumphs; the egg hatches into an elephant-bird, while the planet is saved and respected by the others. He is very popular because of his big heart and respectful compassion, which makes him more humorous.
Document 9: Bartholomew Cubbins: Bartholomew Cubbins is a fictional page and the hero of two children's books by Dr. Seuss: "The 500 Hats of Bartholomew Cubbins" (1938) and "Bartholomew and the Oobleck" (1949). Besides the two books about him—and the stage adaptations of them—Bartholomew Cubbins also appears as a character in the TV show "The Wubbulous World of Dr. Seuss". Moreover, he is mentioned in a song by songwriter Bill Pere. Seuss's only film, "The 5000 Fingers of Dr. T", has a main character named Bartholomew "Collins", who, like his namesake, is a young boy who is wiser than the adults around him.
Document 10: Sylvester and the Magic Pebble: Sylvester and the Magic Pebble is a children's picture book written and illustrated by William Steig. It earned him the Caldecott Medal (1970), his first of many Caldecott and Newbery Medal honors. It tells the tale of Sylvester, a donkey from the fictional community of Oatsdale, who collects pebbles "of unusual shape and color." One day he finds a pebble that grants wishes. Immediately afterward, a lion scares Sylvester, and as a defense he wishes himself into a rock--the only thing he could think of at the moment. Unfortunately, the magic pebble falls off the rock, and Sylvester is unable to revert to his donkey form as the pebble must be in contact with the wish-maker to work. The rest of the story deals with the resulting aftermath: Sylvester's personal attempt to change back into his true self and his parents' search for their only son.
Document 11: Dr. Seuss: Theodor Seuss Geisel ( ; March 2, 1904 – September 24, 1991) was an American author, political cartoonist, poet, animator, book publisher, and artist, best known for authoring children's books under the pen name Dr. Seuss ( ). His work includes several of the most popular children's books of all time, selling over 600 million copies and being translated into more than 20 languages by the time of his death.
Document 12: Grinch: The Grinch is a fictional character created by Dr. Seuss. He is best known as the main character of the children's book "How the Grinch Stole Christmas!" (1957).
Document 13: Big Ears (character): Big Ears is a fictional character from Noddy series books by Enid Blyton. In "Noddy Goes to Toyland" he introduces himself as a brownie "or a sort of a hob, or hobgoblin". He explains that though he "hobnobbed" with Noddy who lived in Toytown, he lived in the "hilly, lumpy, bumpy part of town outside of town". He describes his ears as too big, and his striped trousers with the cap which was "either too pointy or not pointy enough". Together with his brother Little-Ears, he is the only non toy in Toyland and Noddy's helper and father-figure. He is described as having a white beard, red cap, blue jacket, red-and-white striped jumper and yellow-and-green trousers. His catchphrase is "You funny little Noddy!"
Document 14: Horton Hears a Who! (TV special): Horton Hears a Who! is a 1970 television special based on the Dr. Seuss book of the same name, "Horton Hears a Who!". It was produced and directed by Chuck Jones – who previously produced the Seuss special "How the Grinch Stole Christmas!" – for MGM Television and first broadcast March 19, 1970 on CBS. The special contains songs with lyrics by Seuss and music by Eugene Poddany, who previously wrote songs for Seuss' book, "The Cat in the Hat Song Book".
Document 15: Horton Hears a Who!: Horton Hears a Who! is a children's book written and illustrated by Theodor Seuss Geisel under the pen name Dr. Seuss and was published in 1954 by Random House.
ground_truth: 1954