Eduard Nikolayevich Uspensky

 Eduard Nikolayevich Uspensky was a Soviet and Russian children's writer and poet, author of over 70 books, as well as a playwright, screenwriter and TV presenter.

 His works have been translated into 25 languages and spawned around 60 cartoon.
Among the characters he created are Cheburashka and Gena the Crocodile, Uncle Fyodor and Kolobki brothers.

 Three from Prostokvashino is a 1978 Soviet animated film based on the 1974 children's book Uncle Fedya, His Dog, and His Cat by Eduard Uspensky.
 The main character is a six-year-old boy who is called "Uncle Fyodor" (voiced by Maria Vinogradova) because he is very serious. After his parents refuse to let him keep the talking cat Matroskin (voiced by Oleg Tabakov), Uncle Fyodor leaves home. With the dog Sharik (voiced by Lev Durov), the three set up a home in the country village Prostokvashino  Простокваша = "soured milk"). There they have many adventures, some involving the local mailman, Pechkin (voiced by Boris Novikov).[