My bookstore, my dream, hard pen calligraphy, where can I buy a3 paper?

Online platforms and offline stores. My bookstore and my dream hard pen calligraphy contest all use A3 paper as plain paper, which is sold in online platforms and offline stores. "My Library, My Dream" rural children's reading practice focuses on promoting Socialism with Chinese characteristics Thought in the new era to take root in the countryside and go deep into the campus, relying on the platform of farmer's bookstore, deeply grasping children's characteristics and habits, and guiding rural children to acquire knowledge, enlighten wisdom, cultivate morality, love the party and socialism, and strengthen the country and rejuvenate the country through reading, practice, essay writing, painting and calligraphy.