Are there any other books pony boy is mentioned in by S.E. Hinton?

Ponyboy Curtis is the main character in S.E. Hinton's The Outsiders, and he is not mentioned in any other books by her.

Hinton has written several other novels, but they all feature different characters and storylines. While there are common themes of teenage struggles and social issues in her books, the characters themselves are unique to each story.