Here are some English books worth referencing:

1. "To Kill a Mockingbird" by Harper Lee - This novel is a classic of American literature, telling a story about racial discrimination and justice. Its concise language is suitable for improving reading comprehension.

2. "1984" by George Orwell - This novel is a classic of dystopian literature, depicting the terror of a totalitarian society. It utilizes complex vocabulary and sentence structures, ideal for enhancing vocabulary and grammar knowledge.

3. "Pride and Prejudice" by Jane Austen - This novel is a classic of British literature, narrating a story about love and social class. It employs some archaic English expressions, beneficial for a deeper understanding of English culture.

4. "The Great Gatsby" by F. Scott Fitzgerald - This novel is a classic of American literature, portraying 1920s American society. It features rich adjectives and metaphors, great for improving writing skills.

5. "The Catcher in the Rye" by J.D. Salinger - This novel is a classic of American literature, telling the story of a misunderstood adolescent. Its colloquial language is perfect for enhancing oral communication skills.

6. "The Lord of the Rings" by J.R.R. Tolkien - This fantasy novel is a classic of British literature, narrating an adventure story about courage and friendship. It includes complex vocabulary and sentence structures, ideal for improving reading comprehension and vocabulary.

7. "The Chronicles of Narnia" by C.S. Lewis - This series of fantasy novels is a classic of British literature, telling the adventures of a group of children in a magical world. Its vivid descriptions and metaphors are great for enhancing imagination and writing skills.

These books cover various genres and styles, suitable for English learners of different levels. By reading these books, one can improve their reading comprehension, vocabulary, grammar skills, and writing abilities, while also gaining a better understanding of English culture and history.