Regulations Governing the Handling of Mail Article 11

Books mentioned in Subparagraph 5, Article 4 of the Act refer to bound printed matters other than newspapers, magazines and catalogues.The catalogue mentioned in Subparagraph 5, Article 4 of the Act refers to documents printed in words, photos or pictures with more than 50% of the contents dedicated to the price, function, specifications and user instructions of goods or services.
中文原文 郵件處理規則第11條
本法第四條第五款所稱書籍,指新聞紙、雜誌、型錄以外,裝訂成冊之圖書冊籍。
本法第四條第五款所稱型錄,指文件內容百分之五十以上為商品或服務之價格、功能、規格及使用方式,以文字、照片或圖片方式印製者。

English translation for reference only; the Chinese text prevails. Not legal advice.