Primary documents, also known as original documents, refer to original documents with certain inventions and new insights, which are created based on the author's own work experience, observations or actual research results. Secondary documents are processed and organized from primary documents Product, that is, a document form formed by documenting the external characteristics of a disordered primary document such as the title, author, source, etc. , or extracting its content into a summary or abstract, and ordering it according to a certain discipline or specialty. According to the above definitions, Which of the following are secondary documents:. ['Xiao Liu\'s "Good Words and Good Sentences" Handbook.', 'Xiao Li organizes the experimental records and writes the articles after processing the data.', 'Catalogue and introduction of new economic books that Xiao Guo received from the publishing house.', 'First aid manual purchased by Xiao Zhao.']