At Mental Floss, here’s one of them:

The Lorax. In case you haven’t read The Lorax, it’s widely recognized as Dr. Seuss’ take on environmentalism and how humans are destroying nature. The logging industry was so upset about the book that some groups within the industry sponsored The Truax, a similar book but from the logging point of view. Another interesting fact: the book used to contain the line, “I hear things are just as bad up in Lake Erie,” but 14 years after the book was published, the Ohio Sea Grant Program wrote to Seuss and told him how much the conditions had improved and implored him to take the line out. Dr. Seuss agreed and said that it wouldn’t be in future editions.