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"?

Context articles: Horton Hears a Who! (TV special)
Mr. Brown Can Moo! Can You?
Horton Hears a Who!
Dr. Seuss bibliography
Oh Say Can You Say?
Horton the Elephant
Horton Hatches the Egg (film)
Horton Principle
Horton Hatches the Egg
Seussical

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".
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.
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.
Theodor Seuss Geisel, better known as Dr. Seuss, published over 60 children's books over the course of his long career.
 Though most were published under his well-known pseudonym, Dr. Seuss, he also authored over a dozen books as Theo.
 LeSieg and one as Rosetta Stone.
 As one of the most popular children's authors of all time, Geisel's books have topped many bestseller lists, sold over 222 million copies, and been translated into more than 15 languages.
 In 2000, when "Publishers Weekly" compiled their list of the best-selling children's books of all time; 16 of the top 100 hardcover books were written by Geisel, including "Green Eggs and Ham", at number 4, "The Cat in the Hat", at number 9, and "One Fish Two Fish Red Fish Blue Fish", at number 13, and "Dr. Seuss's ABC".
 In the years following his death in 1991, several additional books based on his sketches and notes were published, including "Hooray for Diffendoofer Day!
" and "Daisy-Head Mayzie".
 Although they were all published under the name Dr. Seuss, only "My Many Colored Days", originally written in 1973, was entirely by Geisel.
Oh Say Can You Say?
 is a children's book written and illustrated by Theodor Geisel under the pen name Dr. Seuss, and published in 1979 by Random House.
 It is a collection of 25 tongue-twisters such as "Oh my brothers!
 Oh my sisters!
 These are Terrible Tongue Twisters!"
 It was Dr. Seuss's last beginner book.
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.
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.
The Horton Principle is a design rule for cryptographic systems and can be expressed as "Authenticate what is being meant, not what is being said".
 The principle is named after the title character in the Dr. Seuss children's book "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.
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.